EPA Document# EPA-740-R1-8010
June 2020
United States	Office of Chemical Safety and
tal Mr m Environmental Protection Agency	Pollution Prevention
Risk Evaluation for
Methylene Chloride
(Dichloromethane, DCM)
CASRN: 75-09-2
H
H
..^Cl
CI
Page 1 of 753

-------
TABLE OF CONTENTS
ACKNOWLEDGEMENTS	23
ABBREVIATIONS	24
EXECUTIVE SUMMARY	30
1	INTRODUCTION	42
1.1	Physical and Chemical Properties	43
1.2	Uses and Production Volume	44
1.3	Regulatory and Assessment History	45
1.4	Scope of the Evaluation	47
1.4.1	Conditions of Use Included in the Risk Evaluation	47
1.4.2	Exposure Pathways and Risks Addressed by Other EPA-Administered Statutes	56
1.4.3	Conceptual Models	64
1.5	Systematic Review	67
1.5.1 Data and Information Collection	67
2	EXPOSURES	74
2.1	Fate and Transport	74
2.1.1	Fate and Transport Approach and Methodology	74
2.1.2	Summary of Fate and Transport	76
2.1.3	Key Sources of Uncertainty in Fate and Transport Assessment	78
2.2	Releases to the Environment	79
2.2.1	Water Release Assessment Approach and Methodology	79
2.2.2	Water Release Estimates by Occupational Exposure Scenario	80
2.2.2.1	Manufacturing	80
2.2.2.2	Processing as a Reactant	82
2.2.2.3	Processing - Incorporation into Formulation, Mixture, or Reaction Product	82
2.2.2.4	Repackaging	83
2.2.2.5	Batch Open-Top Vapor Degreasing	84
2.2.2.6	Conveyorized Vapor Degreasing	84
2.2.2.7	Cold Cleaning	84
2.2.2.8	Commercial Aerosol Products	85
2.2.2.9	Adhesives and Sealants	85
2.2.2.10	Paints and Coatings	85
2.2.2.11	Adhesive and Caulk Removers	85
2.2.2.12	Fabric Finishing	85
2.2.2.13	Spot Cleaning	85
2.2.2.14	Cellulose Triacetate Film Production	86
2.2.2.15	Flexible Polyurethane Foam Manufacturing	86
2.2.2.16	Laboratory Use	87
2.2.2.17	Plastic Product Manufacturing	87
2.2.2.18	Lithographic Printing Plate Cleaning	88
2.2.2.19	Non-Aerosol Commercial Uses	89
2.2.2.20	Waste Handling, Disposal, Treatment, and Recycling	89
2.2.2.21	Other Unclassified Facilities	90
2.2.3	Summary of Water Release Assessment	91
2.3	Environmental Exposures	92
Page 2 of 753

-------
2.3.1	Environmental Exposures Approach and Methodology	92
2.3.1.1	Methodology for Obtaining Measured Surface Water Concentrations	93
2.3.1.2	Methodology for Modeling Surface Water Concentrations from Facility Releases (E-
FAST 2014)	94
2.3.1.2.1	E-FAST Calculations	94
2.3.1.2.2	Model Inputs	96
2.3.1.3	Methodology for Geospatial Analysis of Measured Surface Water Monitoring and
Modeled Facility Releases	97
2.3.2	Environmental Exposure Results	98
2.3.2.1	Measured Surface Water Concentrations	98
2.3.2.2	E-F AST Modeling Results	102
2.3.2.3	Geospatial Analysis	103
2.4 Human Exposures	113
2.4.1	Occupational Exposures	118
2.4.1.1	Occupational Exposures Approach and Methodology	119
2.4.1.2	Occupational Exposure Estimates by Scenario	129
2.4.1.2.1	Manufacturing	131
2.4.1.2.2	Processing as aReactant	133
2.4.1.2.3	Processing - Incorporation into Formulation, Mixture, or Reaction Product	136
2.4.1.2.4	Repackaging	139
2.4.1.2.5	Batch Open-Top Vapor Degreasing	141
2.4.1.2.6	Conveyorized Vapor Degreasing	142
2.4.1.2.7	Cold Cleaning	144
2.4.1.2.8	Commercial Aerosol Products (Aerosol Degreasing, Aerosol Lubricants,
Automotive Care Products)	146
2.4.1.2.9	Adhesives and Sealants	149
2.4.1.2.10	Paints and Coatings	154
2.4.1.2.11	Adhesive and Caulk Removers	159
2.4.1.2.12	Fabric Finishing	161
2.4.1.2.13	Spot Cleaning	164
2.4.1.2.14	Cellulose Triacetate Film Production	166
2.4.1.2.15	Flexible Polyurethane Foam Manufacturing	168
2.4.1.2.16	Laboratory Use	171
2.4.1.2.17	Plastic Product Manufacturing	175
2.4.1.2.18	Lithographic Printing Plate Cleaning	180
2.4.1.2.19	Miscellaneous Non-Aerosol Industrial and Commercial Uses	182
2.4.1.2.20	Waste Handling, Disposal, Treatment, and Recycling	184
2.4.1.3	Summary of Occupational Exposure Assessment	187
2.4.2	Consumer Exposures	191
2.4.2.1	Consumer Exposures Approach and Methodology	191
2.4.2.2	Exposure Routes	192
Page 3 of 753

-------
2.4.2.3	Modeling Approach	193
2.4.2.3.1	CEM Model and Scenarios (e.g., table of scenarios),	194
2.4.2.3.2	CEM Scenario Inputs	196
2.4.2.3.3	Sensitivity Analysis	204
2.4.2.4	Consumer Use Scenario Specific Results	204
2.4.2.4.1	Adhesives	204
2.4.2.4.2	Adhesive Remover	206
2.4.2.4.3	Auto AC Leak Sealer	207
2.4.2.4.4	Auto AC Refrigerant	207
2.4.2.4.5	Brake Cleaner	208
2.4.2.4.6	Brush Cleaner	209
2.4.2.4.7	Carbon Remover	210
2.4.2.4.8	Carburetor Cleaner	211
2.4.2.4.9	Coil Cleaner	212
2.4.2.4.10	Cold Pipe Insulation Spray	213
2.4.2.4.11	Electronics Cleaner	214
2.4.2.4.12	Engine Cleaner	215
2.4.2.4.13	Gasket Remover	216
2.4.2.4.14	Sealants	217
2.4.2.4.15	Weld Spatter Protectant	218
2.4.2.5	Monitoring Data	219
2.4.2.5.1	Indoor Residential Air	219
2.4.2.5.2	Personal Breathing Zone Data	221
2.4.2.6	Modeling Confidence in Consumer Exposure Results	223
3 HAZARDS	227
3.1	Environmental Hazards	227
3.1.1	Approach and Methodology	227
3.1.2	Hazard Identification	227
3.1.3	Weight of Scientific Evidence	233
3.1.4	Concentrations of Concern (COC)	235
3.1.5	Summary of Environmental Hazard	237
3.2	Human Health Hazards	239
3.2.1	Approach and Methodology	239
3.2.2	Toxicokinetics	243
3.2.3	Hazard Identification	245
3.2,3.1 Non-Cancer Hazards	246
3.2.3.1.1	Toxicity from Acute/Short-Term Exposure	246
3.2.3.1.2	Liver Effects	255
3.2.3.1.3	Immune System Effects	260
3.2.3.1.4	Nervous System Effects	263
Page 4 of 753

-------
3.2.3.1.5	Reproductive and Developmental Effects	267
3.2.3.1.6	Irritation/Burns	269
3,2,3,2 Cancer Hazards	270
3.2.3.2.1	Carcinogenicity	271
3.2.3.2.2	Genotoxicity and Other Mechanistic Information	282
3.2.4	Weight of Scientific Evidence	285
3.2.4.1	Non-Cancer Hazards	285
3.2.4.1.1	Toxicity from Acute/Short-Term Exposure	285
3.2.4.1.2	Liver Effects	286
3.2.4.1.3	Immune System Effects	287
3.2.4.1.4	Nervous System Effects	288
3.2.4.1.5	Reproductive and Developmental Effects	289
3.2.4.1.6	Irritation/Burns	290
3.2.4.2	Genotoxicity and Carcinogenicity	290
3.2.5	Dose-Response Assessment	294
3.2.5.1	Selection of Studies for Dose-Response Assessment	294
3.2.5.1.1	Toxicity from Acute/Short-Term Exposure	294
3.2.5.1.2	Toxicity from Chronic Exposure	295
3.2.5.2	Derivation of PODs and UFs for Benchmark Margins of Exposures (MOEs)	301
3.2.5.2.1	PODs for Acute/Short-term Inhalation Exposure	301
3.2.5.2.2	PODs for Chronic Inhalation Exposure	304
3.2.5.2.3	Route to Route Extrapolation for Dermal PODs	311
3.2.5.3	PODs for Human Health Hazard Endpoints and Confidence Levels	312
4 RISK CHARACTERIZATION	314
4.1	Risk Conclusions	314
4.1.1	Summary of Environmental Ri sk	314
4.1.2	Summary of Risk Estimates for Inhalation and Dermal Exposures to Workers	318
4.1.3	Summary of Risk Estimates for Inhalation and Dermal Exposures to Consumers and
Bystanders	333
4.2	Environmental Risk	345
4.2.1	Risk Estimation Approach	345
4.2.2	Risk Estimation for Aquatic Environment	346
4.2.3	Risk Estimation for Sediment	359
4.2.4	Risk Estimation for Terrestrial	359
4.3	Human Health Risk	360
4.3.1	Risk Estimation Approach	360
4.3.2	Risk Estimation for Inhalation and Dermal Exposures	365
4.3.2.1 Risk Estimation for Inhalation Exposures to Workers	365
4.3.2.1.1	Occupational Inhalation Exposure Summary and PPE Use Determination by OES
365
4.3.2.1.2	Manufacturing	370
4.3.2.1.3	Processing as aReactant	372
Page 5 of 753

-------
4.3.2.1.4	Processing - Incorporation into Formulation, Mixture, or Reaction Product	373
4.3.2.1.5	Repackaging	375
4.3.2.1.6	Waste Handling, Disposal, Treatment, and Recycling	376
4.3.2.1.7	Batch Open-Top Vapor Degreasing	378
4.3.2.1.8	Conveyorized Vapor Degreasing	379
4.3.2.1.9	Cold Cleaning	381
4.3.2.1.10	Commercial Aerosol Products (Aerosol Degreasing, Aerosol Lubricants,
Automotive Care Products)	382
4.3.2.1.11	Adhesives and Sealants	383
4.3.2.1.12	Paints and Coatings	386
4.3.2.1.13	Adhesive and Caulk Removers	390
4.3.2.1.14	Miscellaneous Non-Aerosol Commercial and Industrial Uses	392
4.3.2.1.15	Fabric Finishing	394
4.3.2.1.16	Spot Cleaning	395
4.3.2.1.17	Cellulose Triacetate Film Production	396
4.3.2.1.18	Plastic Product Manufacturing	398
4.3.2.1.19	Flexible Polyurethane Foam Manufacturing	399
4.3.2.1.20	Laboratory Use	401
4.3.2.1.21	Lithographic Printing Plate Cleaning	402
4.3.2.2	Risk Estimation for Dermal Exposures to Workers	404
4.3.2.3	Risk Estimation for Inhalation and Dermal Exposures to Consumers	410
4.3.2.3.1	Brake Cleaner	410
4.3.2.3.2	Carbon Remover	411
4.3.2.3.3	Carburetor Cleaner	413
4.3.2.3.4	Coil Cleaner	414
4.3.2.3.5	Electronics Cleaner	415
4.3.2.3.6	Engine Cleaner	416
4.3.2.3.7	Gasket Remover	418
4.3.2.3.8	Adhesives	419
4.3.2.3.9	Auto Leak Sealer	420
4.3.2.3.10	Brush Cleaner	421
4.3.2.3.11	Adhesive Remover	422
4.3.2.3.12	Auto AC Refrigerant	423
4.3.2.3.13	Cold Pipe Insulation Spray	424
4.3.2.3.14	Sealants	426
4.3.2.3.15	Weld Spatter Protectant	427
Assumptions and Key Sources of Uncertainty	428
Page 6 of 753

-------
4.4.1	Key Assumptions and Uncertainties in the Environmental Exposure Assessment	428
4.4.2	Key Assumptions and Uncertainties in the Occupational Exposure Assessment	431
4.4.2.1	Occupational Inhalation Exposure Concentration Estimates	431
4.4.2.2	OSHA Data Analysis	433
4.4.2.3	Near-Field/Far-Field Model Framework	434
4.4.2.3.1	Vapor Degreasing Models	435
4.4.2.3.2	Brake Servicing Model	435
4.4.2.4	Occupational Dermal Exposure Dose Estimates	436
4.4.3	Key Assumptions and Uncertainties in the Consumer Exposure Assessment	436
4.4.4	Key Assumptions and Uncertainties in Environmental Hazards	441
4.4.5	Key Assumptions and Uncertainties in the Human Health Hazards	442
4.4.6	Key Assumptions and Uncertainties in the Environmental Risk Estimation	445
4.4.7	Key Assumptions and Uncertainties in the Human Health Risk Estimation	447
4.5	Potentially Exposed or Susceptible Subpopulations	450
4.6	Aggregate and Sentinel Exposures	452
5 UNREASONABLE RISK DETERMINATION	453
5.1	Overview	453
5.1.1	Human Health	453
5.1.1.1	Non-Cancer Risk Estimates	454
5.1.1.2	Cancer Risk Estimates	454
5.1.1.3	Determining Unreasonable Risk of Injury to Health	455
5.1.2	Environment	456
5.1.2,1 Determining Unreasonable Risk of Injury to the Environment	457
5.2	Detailed Unreasonable Risk Determinations by Condition of Use	457
5.2.1 Human Health	462
5.2.1.1	Manufacturing - Domestic Manufacturing - Manufacturing (Domestic manufacture)
462
5.2.1.2	Manufacturing - Import - Import (Import)	463
5.2.1.3	Processing - Processing as a reactant - Intermediate in industrial gas manufacturing;
intermediate for pesticide, fertilizer, and other agricultural chemical manufacturing; use in
petrochemical manufacturing; intermediate for other chemicals (Processing as a reactant)	464
5.2.1.4 Processing - Incorporation into formulation, mixture, or reaction products - Solvents
for cleaning or degreasing; solvents which become part of product formulation or mixture;
propellants and blowing agents for all other chemical products and preparation manufacturing;
propellants and blowing agents for plastic product manufacturing; paints and coating additives
not described by other codes; laboratory chemicals for all other chemical product and preparation
manufacturing; laboratory chemicals for other industrial sectors; processing aid, not otherwise
listed for petrochemical manufacturing; adhesive and sealant chemicals in adhesive
manufacturing; oil and gas drilling, extraction, and support activities (Processing into a
formulation, mixture, or reaction product)	465
5.2.1.5	Processing - Repackaging - Solvents (which become part of product formulation or
mixture) for all other chemical product and preparation manufacturing; all other chemical product
and preparation manufacturing (Repackaging)	466
5.2.1.6	Processing - Recycling - Recycling (Recycling)	467
5.2.1.7	Distribution in Commerce - Distribution - Distribution	468
5.2.1.8	Industrial/Commercial Use - Solvents (for cleaning or degreasing) - Batch vapor
degreaser (e.g., open-top, closed-loop) (Solvent for batch vapor degreasing)	468
Page 7 of 753

-------
5.2.1.9	Industrial/Commercial Use - Solvents (for cleaning or degreasing) - In-line vapor
degreaser (e.g., conveyorized, web cleaner) (Solvent for in-line vapor degreasing)	469
5.2.1.10	Industrial/Commercial Use - Solvents (for cleaning or degreasing) - Cold cleaner
(Solvent for cold cleaning)	471
5.2.1.11	Industrial/Commercial Use - Solvents (for cleaning or degreasing) - Aerosol spray
degreaser/cleaner (Solvent for aerosol spray degreaser/cleaner)	472
5.2.1.12	Industrial/Commercial Use - Adhesives and sealants - Single component glues and
adhesives and sealants and caulks (Adhesives, sealants and caulks)	473
5.2.1.13	Industrial/Commercial Use - Paints and coatings use including commercial paint and
coating removers - Paints and coatings use (Paints and coatings)	474
5.2.1.14	Industrial/Commercial Use - Paints and coatings including commercial paint and
coating removers - Commercial paint and coating removers, including furniture refinisher (Paint
and coating removers)	475
5.2.1.15	Industrial/Commercial Use - Paints and coatings including commercial paint and
coating removers - Adhesive/caulk remover (Adhesive and caulk removers)	476
5.2.1.16	Industrial/Commercial Use - Metal products not covered elsewhere - Degreasers -
aerosol degreasers and cleaners (Metal aerosol degreasers)	477
5.2.1.17	Industrial/Commercial Use - Metal products not covered elsewhere - Degreasers - non-
aerosol degreasers and cleaners (Metal non-aerosol degreasers)	478
5.2.1.18	Industrial/Commercial Use - Fabric, textile and leather products not covered elsewhere
- Textile finishing and impregnating/surface treatment products (Finishing products for fabric,
textiles and leather)	479
5.2.1.19	Industrial/Commercial Use - Automotive care products - Functional fluids for air
conditioners: refrigerant, treatment, leak sealer (Automotive care products (functional fluids for
air conditioners))	481
5.2.1.20	Industrial/Commercial Use - Automotive care products - Interior car care - spot
remover (Automotive care products (interior care))	482
5.2.1.21	Industrial/Commercial Use - Automotive care products - Degreasers: gasket remover,
transmission cleaners, carburetor cleaner, brake quieter/cleaner (Automotive care products
(degreasers))	483
5.2.1.22	Industrial/Commercial Use - Apparel and footwear care products - Post-market waxes
and polishes applied to footwear (Apparel and footwear care products)	484
5.2.1.23	Industrial/Commercial Use - Laundry and dishwashing products - Spot remover for
apparel and textiles (Spot removers for apparel and textiles)	484
5.2.1.24	Industrial/Commercial Use - Lubricant and greases - Liquid lubricants and greases
(Liquid lubricants and greases)	485
5.2.1.25	Industrial/Commercial Use - Lubricants and greases - Spray lubricants and greases
(Spray lubricants and greases)	487
5.2.1.26	Industrial/Commercial Use - Lubricants and greases - Degreasers - Aerosol degreasers
and cleaners (Aerosol degreasers and cleaners)	488
5.2.1.27	Industrial/Commercial Use - Lubricants and greases - Non-aerosol degreasers and
cleaners (Non-aerosol degreasers and cleaners)	489
5.2.1.28	Industrial/Commercial Use - Building/construction materials not covered elsewhere -
Cold pipe insulation (Cold pipe insulations)	490
5.2.1.29	Industrial/Commercial Use - Solvents (which become part of product formulation or
mixture) - All other chemical product and preparation manufacturing (Solvent that becomes part
of a formulation or mixture)	491
5.2.1.30	Industrial/Commercial Use - Processing aid not otherwise listed - In multiple
manufacturing sectors (Processing aid)	492
Page 8 of 753

-------
5.2.1.31	Industrial/Commercial Use - Propellants and blowing agents - Flexible polyurethane
foam manufacturing (Propellant and blowing agent)	493
5.2.1.32	Industrial/Commercial Use - Other uses - Laboratory chemicals - all other chemical
product and preparation manufacturing (Laboratory chemical)	494
5.2.1.33	Industrial/Commercial Use - Other uses - Electrical equipment, appliance, and
component manufacturing (Electrical equipment, appliance, and component manufacturing) .. 495
5.2.1.34	Industrial/Commercial Use - Other uses - Plastic and rubber products (plastic product
manufacturing) (Plastic and rubber products manufacturing)	496
5.2.1.35	Industrial/Commercial Use - Other uses - Plastic and rubber products (cellulose
triacetate film production) (Cellulose triacetate film production)	497
5.2.1.36	Industrial/Commercial Use - Other uses - Anti-adhesive agent - anti-spatter welding
aerosol (Anti-spatter welding aerosol)	498
5.2.1.37	Industrial/Commercial Use - Other uses - Oil and gas drilling, extraction, and support
activities (Oil and gas drilling, extraction, and support activities)	499
5.2.1.38	Industrial/Commercial Use - Other uses - Toys, playground, and sporting equipment -
including novelty articles (Toys, playground and sporting equipment)	500
5.2.1.39	Industrial/Commercial Use - Other uses - Lithographic printing cleaner (Lithographic
printing plate cleaner)	501
5.2.1.40	Industrial/Commercial Use - Other uses - Carbon remover, wood floor cleaner, brush
cleaner (Carbon remover, wood floor cleaner and brush cleaner)	502
5.2.1.41	Consumer Use - Solvents (for cleaning or degreasing) - Aerosol spray
degreaser/cleaner (Solvent in Aerosol degreasers/cleaners)	503
5.2.1.42	Consumer Use - Adhesives and sealants - Single component glues and adhesives and
sealants and caulks (Adhesives and sealants)	504
5.2.1.43	Consumer Use - Paints and coatings- Paints and coatings (Brush Cleaners for paints
and coatings)	505
5.2.1.44	Consumer Use - Paints and coatings - Adhesive/caulk remover (Adhesive and caulk
removers)	506
5.2.1.45	Consumer Use - Metal products not covered elsewhere - Degreasers - aerosol and non-
aerosol degreasers (Metal degreasers)	507
5.2.1.46	Consumer Use - Automotive care products - Functional fluids for air conditioners:
refrigerant, treatment, leak sealer (Automotive care products (functional fluids for air
conditioners))	507
5.2.1.47	Consumer Use - Automotive care products - Degreasers: gasket remover, transmission
cleaners, carburetor (Automotive care products (degreasers))	508
5.2.1.48	Consumer Use - Lubricants and greases - Liquid and spray lubricants and greases;
degreasers - Aerosol and non-aerosol degreasers and cleaners (Lubricants and greases)	509
5.2.1.49	Consumer Use - Building/ construction materials not covered elsewhere - Cold pipe
insulation (Cold pipe insulation)	510
5.2.1.50	Consumer Use - Arts, crafts and hobby materials - Crafting glue and cement/concrete
(Arts, crafts and hobby materials glue)	511
5.2.1.51	Consumer Use - Other Uses - Anti-adhesive agent - anti-spatter welding aerosol (Anti-
spatter welding aerosol)	512
5.2.1.52	Consumer Use - Other Uses - Carbon Remover and brush cleaner (Carbon remover and
other brush cleaner)	513
5.2.1.53	Disposal - Disposal - Industrial pre-treatment; industrial wastewater treatment; publicly
owned treatment works (POTW); underground injection; municipal landfill; hazardous landfill;
other land disposal; municipal waste incinerator; hazardous waste incinerator; off-site waste
transfer (Disposal)	513
Page 9 of 753

-------
5.2.2 Environment	514
5.3	Changes to the Unreasonable Risk Determination from Draft Risk Evaluation to Final Risk
Evaluation	515
5.4	Unreasonable Risk Determination Conclusion	517
5.4.1	5.4.1 No Unreasonable Risk Determinations	517
5.4.2	Unreasonable Risk Determinations	518
REFERENCES	521
APPENDICES	551
Appendix A REGULATORY HISTORY	551
A.l Federal Laws and Regulations																...551
A.2 State Laws and Regulations												...561
A.3 International Laws and Regulations....									............563
Appendix B	LIST OF SUPPLEMENTAL DOCUMENTS	565
Appendix C	FATE AND TRANSPORT	567
Appendix D	RELEASES TO THE ENVIRONMENT	568
Appendix E	ENVIRONMENTAL EXPOSURES	573
Appendix F	OCCUPATIONAL EXPOSURES	607
F. 1 Information on Respirators and Gloves for Methylene Chloride including Paint and Coating
Removal																		...........607
F.2	Summary of Information on Gloves from SDS for Methylene Chloride and Formulations
containing Methylene Chloride....................															613
Appendix G CONSUMER EXPOSURES	617
G.l	Consumer Exposure																	..617
G.2 Consumer Inhalation Exposure..											.....617
G.3 Consumer Dermal Exposure														..618
G.3.1 Comparison of Two Dermal Model Methodologies to Calculate Acute Dose Rate (ADR) 618
G.3.2 Comparison of Estimated ADRs Across the Two Dermal Models	621
G.4	Sensitivity Analysis																							..626
G.4.1 Sensitivity Analysis of Overall CEM Model	626
G.4.2 Sensitivity of Dermal Modeling	628
G.4.2.1	Duration of Use	628
G.4.2.2	Fraction Absorbed	628
G.4.2.3	Mass Terms	629
G.4.2.4	Permeability Coefficients	630
G.4.2.5	Other Parameters	630
G.4.2.6	Selection of Dermal Models	630
Appendix H ENVIRONMENTAL HAZARDS	631
H.	1 Aquatic Toxicity Data Extraction Table for Methylene Chloride.							....631
H.2	Risk Quotients for All Facilities Modeled in E-FAST										.645
Appendix I DERIVATION OF IUR AND NON-CANCER HUMAN EQUIVALENT
CONCENTRATION FOR CHRONIC EXPOSURES	682
I.1	Cancer Inhalation Unit Risk....................											...................682
Page 10 of 753

-------
1.2 Non-Cancer Hazard Value										.......684
Appendix J CASE REPORTS OF FATALITIES ASSOCIATED WITH METHYLENE
CHLORIDE EXPOSURE	686
Appendix K SUMMARY OF METHYLENE CHLORIDE GENOTOXICITY DATA	691
Appendix L SUMMARY OF OCCUPATIONAL EXPOSURES AND RISKS FOR PAINT AND
COATING REMOVERS	708
Appendix M EVIDENCE INTEGRATION OF IMMUNE SYSTEM EFFECTS	748
Page 11 of 753

-------
LIST OF TABLES
Table 1-1. Physical and Chemical Properties of Methylene Chloride	43
Table 1-2. Production Volume of Methylene Chloride in CDR Reporting Period (2012 to 2015)a	45
Table 1-3. Assessment History of Methylene Chloride	46
Table 1-4. Categories and Subcategories of Conditions of Use Included in the Scope of the Risk
Evaluation	49
Table 2-1. Environmental Fate Characteristics of Methylene Chloride	75
Table 2-2. Reported TRI Releases for Organic Chemical Manufacturing Facilities	81
Table 2-3. Reported 2016 TRI and DMR Releases for Potential Processing as Reactant Facilities	82
Table 2-4. Potential Industries Conducting Methylene Chloride Processing - Incorporation into
Formulation, Mixture, or Reaction Product in 2016 TRI or DMR	82
Table 2-5. Reported 2016 TRI and DMR Releases for Potential ProcessingIncorporation into
Formulation, Mixture, or Reaction Product Facilities	82
Table 2-6. Reported 2016 TRI and DMR Releases for Repackaging Facilities	84
Table 2-7. Surface Water Releases of Methylene Chloride During Spot Cleaning	86
Table 2-8. Reported 2016 TRI and DMR Releases for CTA Manufacturing Facilities	86
Table 2-9. Water Releases Reported in 2016 TRI for Polyurethane Foam Manufacturing	87
Table 2-10. Potential Industries Conducting Plastics Product Manufacturing in 2016 TRI or DMR	87
Table 2-11. Reported 2016 TRI and DMR Releases for Potential Plastics Product Manufacturing
Facilities	87
Table 2-12. Reported 2016 TRI and DMR Releases for Potential Lithographic Printing Facilities	88
Table 2-13. Potential Industries Conducting Waste Handling, Disposal, Treatment, and Recycling in
2016 TRI or DMR	89
Table 2-14. Reported 2016 TRI and DMR Releases for Potential Recycling/Disposal Facilities	89
Table 2-15. Reported 2016 TRI and DMR Releases for Other Unclassified Facilities	90
Table 2-16. Measured Concentrations of Methylene Chloride in Surface Water Obtained from the Water
Quality Portal (WQP): 2013-2017a	99
Table 2-17. Sample Information for Water Quality Exchange (WQX) Surface Water Observations With
Concentrations Above the Reported Detection Limit: Year 2016a	100
Table 2-18. Summary of Published Literature with Surface Water Monitoring Data	101
Table 2-19. Summary of Surface Water Concentrations by Occupational Exposure Scenarios (OES) for
Maximum Days of Release Scenario	102
Table 2-20. Summary of Surface Water Concentrations by Occupational Exposure Summary (OES) for
20 Days of Release Scenario	103
Table 2-21. Co-Location of Facility Releases and Monitoring Sites within HUC 8 Boundaries (Year
2016)	Ill
Table 2-22. Crosswalk of Conditions of Use to Occupational and Consumer Scenarios Assessed in the
Risk Evaluation	114
Table 2-23. Summary of Pre- and Post-Rule Exposure Concentrations for Industries with Largest
Number of Data Points	123
able 2-24. Summary of Pre- and Post-Rule Exposure Concentrations Mapped to Occupational Exposure
Scenarios	124
Table 2-25. Assigned Protection Factors for Respirators in OSHA Standard 29 CFR 1910.134a	125
Table 2-26. Glove Protection Factors for Different Dermal Protection Strategies from ECETOC TRA v3
	128
Table 2-27. Estimated Numbers of Workers in the Assessed Industry Scenarios for Methylene Chloride
	130
Table 2-28. Worker Exposure to Methylene Chloride During Manufacturing3	132
Page 12 of 753

-------
Table 2-29. Short-Term Worker Exposure to Methylene Chloride During Manufacturing	132
Table 2-30. Summary of Dermal Exposure Doses to Methylene Chloride for Manufacturing	133
Table 2-31. Worker Exposure to Methylene Chloride During Processing as a Reactant During
Fluorochemicals Manufacturing51	134
Table 2-32. Summary of Personal Short-Term Exposure Data for Methylene Chloride During Processing
as a Reactant	135
Table 2-33. Summary of Dermal Exposure Doses to Methylene Chloride for Processing as a Reactant
	136
Table 2-34. Worker Exposure to Methylene Chloride During Processing - Incorporation into
Formulation, Mixture, or Reaction Producta	137
Table 2-35. Summary of Dermal Exposure Doses to Methylene Chloride for Processing - Incorporation
into Formulation, Mixture, or Reaction Product	138
Table 2-36. Worker Exposure to Methylene Chloride During Repackaging51	139
Table 2-37. Summary of Personal Short-Term Exposure Data for Methylene Chloride During
Repackaging	139
Table 2-38. Summary of Dermal Exposure Doses to Methylene Chloride for Repackaging	140
Table 2-39. Statistical Summary of Methylene Chloride 8-hr TWA Exposures (ADC and LADC) for
Workers and ONUs for Batch Open-Top Vapor Degreasing	141
Table 2-40. Summary of Dermal Exposure Doses to Methylene Chloride for Batch Open-Top Vapor
Degreasing	142
Table 2-41. Statistical Summary of Methylene Chloride 8-hr TWA Exposures (ADC and LADC) for
Workers and ONUs for Conveyorized Vapor Degreasing	143
Table 2-42. Summary of Dermal Exposure Doses to Methylene Chloride for Conveyorized Vapor
Degreasing	143
Table 2-43. Worker Exposure to Methylene Chloride During Cold Cleaning51	145
Table 2-44. Summary of Dermal Exposure Doses to Methylene Chloride for Cold Cleaning	146
Table 2-45. Worker Exposure to Methylene Chloride During Aerosol Product Applications Based on
Monitoring Dataa	147
Table 2-46. Statistical Summary of Methylene Chloride 8-hr and 1-hr TWA Exposures (ADC and
LADC) for Workers and ONUs for Aerosol Products Based on Modeling	148
Table 2-47. Summary of Dermal Exposure Doses to Methylene Chloride for Commercial Aerosol
Product Uses	148
Table 2-48. Worker Exposure to Methylene Chloride During Industrial Non-Spray Adhesives Usea ..151
Table 2-49. Worker Exposure to Methylene Chloride During Industrial Spray Adhesives Usea	151
Table 2-50. Worker Exposure to Methylene Chloride During Adhesives and Sealants Use (Unknown
Application Method)51	151
Table 2-51. Summary of Personal Short-Term Exposure Data for Methylene Chloride During Industrial
Adhesives Use	152
Table 2-52. Summary of Dermal Exposure Doses to Methylene Chloride for Adhesives and Sealants
Uses	153
Table 2-53. Worker Exposure to Methylene Chloride During Paint/Coating Spray Application51	155
Table 2-54. Worker Exposure to Methylene Chloride During Paint/Coating Application (Unknown
Application Method)51	156
Table 2-55. Summary of Personal Short-Term Exposure Data for Methylene Chloride During
Paint/Coating Use	157
Table 2-56. Summary of Dermal Exposure Doses to Methylene Chloride for Paint and Coatings Uses
	158
Table 2-57. Worker Exposure to Methylene Chloride for During Use of Adhesive and Caulk Removers51
	160
Page 13 of 753

-------
Table 2-58. Short-Term Exposure to Methylene Chloride During Use of Adhesive and Caulk Removers
	160
Table 2-59. Summary of Dermal Exposure Doses to Methylene Chloride for Adhesive and Caulk
Removers	161
Table 2-60. Worker and ONU Exposure to Methylene Chloride During Fabric Finishing	162
Table 2-61. Summary of Personal Short-Term Exposure Data for Methylene Chloride During Fabric
Finishing	163
Table 2-62. Summary of Dermal Exposure Doses to Methylene Chloride for Fabric Finishing	163
Table 2-63. Worker Exposure to Methylene Chloride for During Spot Cleaning51	165
Table 2-64. Summary of Dermal Exposure Doses to Methylene Chloride for Spot Cleaning	165
Table 2-65. Worker Exposure to Methylene Chloride During CTA Film Manufacturing3	167
Table 2-66. Summary of Dermal Exposure Doses to Methylene Chloride for CTA Film Manufacturing
	167
Table 2-67. Worker Exposure to Methylene Chloride During Industrial Polyurethane Foam
Manufacturing3	169
Table 2-68. Summary of Personal Short-Term Exposure Data for Methylene Chloride During
Polyurethane Foam Manufacturing	169
Table 2-69. Summary of Dermal Exposure Doses to Methylene Chloride for Polyurethane Foam
Manufacturing	170
Table 2-70. Worker Exposure to Methylene Chloride During Laboratory Usea	172
Table 2-71. Worker Personal Short-Term Exposure Data for Methylene Chloride During Laboratory Use
	172
Table 2-72. Summary of Dermal Exposure Doses to Methylene Chloride for Laboratory Use	174
Table 2-73. Worker and ONU Exposure to Methylene Chloride During Plastic Product Manufacturing
	176
Table 2-74. Worker Short-Term Exposure Data for Methylene Chloride During Plastic Product
Manufacturing	178
Table 2-75. Summary of Dermal Exposure Doses to Methylene Chloride for Plastic Product
Manufacturing	179
Table 2-76. Worker Exposure to Methylene Chloride During Printing Plate Cleaning3	181
Table 2-77. Worker Short-Term Exposure Data for Methylene Chloride During Printing Plate Cleaning
	181
Table 2-78. Summary of Dermal Exposure Doses to Methylene Chloride for Lithographic Printing Plate
Cleaner	182
Table 2-79. Worker Exposure to Methylene Chloride During Miscellaneous Industrial and Commercial
Non-Aerosol Usea	183
Table 2-80. Summary of Dermal Exposure Doses to Methylene Chloride for Miscellaneous Industrial
and Commercial Non-Aerosol Use	184
Table 2-81. Worker Exposure to Methylene Chloride During Waste Handling and Disposal51	185
Table 2-82. Worker Short-Term Exposure Data for Methylene Chloride During Waste Handling and
Disposal	186
Table 2-83. Summary of Dermal Exposure Doses to Methylene Chloride for Waste Handling, Disposal,
Treatment, and Recycling	186
Table 2-84. Summary of Acute and Chronic Inhalation Exposures to Methylene Chloride for Central and
Higher-End Scenarios by Occupational Exposure Scenario	187
Table 2-85. Summary of Dermal Exposure Doses to Methylene Chloride by Occupational Exposure
Scenario and Potential Glove Use	190
Table 2-86. Evaluated Consumer Uses for Products Containing Methylene Chloride	191
Table 2-87. Fixed Consumer Use Scenario Modeling Parameters	198
Page 14 of 753

-------
Table 2-88. Consumer Use Non-Varying Scenario Specific Inputs for Evaluation of Inhalation and
Dermal Exposure	200
Table 2-89. Consumer Use Scenario Specific Values of Duration of Use, Weight Fraction, and Mass of
Product Used Derived from WU.S. EPA (1987)	202
Table 2-90. Consumer User and Bystander Inhalation Exposure to Methylene Chloride During Use as an
Adhesive	205
Table 2-91. Consumer Dermal Exposure to Methylene Chloride During Use as an Adhesive	205
Table 2-92. Consumer User and Bystander Inhalation Exposure to Methylene Chloride During Use as an
Adhesives Remover	206
Table 2-93. Consumer Dermal Exposure to Methylene Chloride During Use as an Adhesive Remover
	206
Table 2-94. Consumer User and Bystander Inhalation Exposure to Methylene Chloride During Auto
Leak Sealer Use	207
Table 2-95. Consumer Dermal Exposure to Methylene Chloride During Use as an Auto Leak Sealer. 207
Table 2-96. Consumer User and Bystander Inhalation Exposure to Methylene Chloride During Auto Air
Conditioning Refrigerant Use	208
Table 2-97. Consumer Dermal Exposure to Methylene Chloride During Use as an Auto Air
Conditioning Refrigerant	208
Table 2-98. Consumer User and Bystander Inhalation Exposure to Methylene Chloride During Use as a
Brake Cleaner	209
Table 2-99. Consumer Dermal Exposure to Methylene Chloride During Use as a Brake Cleaner	209
Table 2-100. Consumer User and Bystander Inhalation Exposure to Methylene Chloride During Use as a
Brush Cleaner	210
Table 2-101. Consumer Dermal Exposure to Methylene Chloride During Use as a Brush Cleaner	210
Table 2-102. Consumer User and Bystander Inhalation Exposure to Methylene Chloride During Use as a
Carbon Remover	211
Table 2-103. Consumer Dermal Exposure to Methylene Chloride During Use as a Carbon Remover. 211
Table 2-104. Consumer User and Bystander Inhalation Exposure to Methylene Chloride During Use as a
Carburetor Cleaner	212
Table 2-105. Consumer Dermal Exposure to Methylene Chloride During Use as a Carburetor Cleaner
	212
Table 2-106. Consumer User and Bystander Inhalation Exposure to Methylene Chloride During use as a
Coil Cleaner	213
Table 2-107. Consumer Dermal Exposure to Methylene Chloride During Use as a Coil Cleaner	213
Table 2-108. Consumer User and Bystander Inhalation Exposure to Methylene Chloride During Cold
Pipe Insulation Spray Use	214
Table 2-109. Consumer Dermal Exposure to Methylene Chloride During Use as a Cold Pipe Insulation
Spray	214
Table 2-110. Consumer User and Bystander Inhalation Exposure to Methylene Chloride During Use as
an Electronics Cleaner	215
Table 2-111. Consumer Dermal Exposure to Methylene Chloride During Use as an Electronics Cleaner
	215
Table 2-112. Consumer User and Bystander Inhalation Exposure to Methylene Chloride During Use as
an Engine Cleaner	216
Table 2-113. Consumer Dermal Exposure to Methylene Chloride During Use as an Engine Cleaner.. 216
Table 2-114. Consumer User and Bystander Inhalation Exposure to Methylene Chloride During Use as a
Gasket Remover	217
Table 2-115. Consumer Dermal Exposure to Methylene Chloride During Use as a Gasket Remover.. 217
Page 15 of 753

-------
Table 2-116. Consumer User and Bystander Inhalation Exposure to Methylene Chloride During Use as a
Sealant	218
Table 2-117. Consumer Dermal Exposure to Methylene Chloride During Use as a Sealant	218
Table 2-118. Consumer User and Bystander Inhalation Exposure to Methylene Chloride During Use as a
Weld Spatter Protectant	219
Table 2-119. Consumer Dermal Exposure to Methylene Chloride During Use as a Weld Spatter
Protectant	219
Table 2-120. Concentrations of Methylene Chloride in the Indoor Air of Residential Homes in the U.S.
and Canada from Studies Identified During Systematic Review	220
Table 2-121. Concentrations of Methylene Chloride in the Personal Breathing Zones of Residents in the
U.S	222
Table 2-122. Confidence in Individual Consumer Conditions of Use Inhalation Exposure Evaluations
	224
Table 2-123. Confidence in individual consumer conditions of use for dermal exposure evaluations.. 225
Table 3-1. Ecological Hazard Characterization of Methylene Chloride for Aquatic Organisms	232
Table 3-2. COCs for Environmental Toxicity	239
Table 3-3. Human Controlled Inhalation Experiments Measuring Effects on the Nervous System* .... 252
Table 3-4. Liver Effects Identified in Chronic and Subchronic Animal Toxicity Studies of Methylene
Chloride	257
Table 3-5. Selected Effect Estimates for Epidemiological Studies of Liver Cancers	271
Table 3-6. Summary of Significantly Increased Liver Tumor Incidences in Inhalation Studies of
Methylene Chloride	272
Table 3-7. Summary of Significantly Increased Liver Tumor Incidences in Oral Studies of Methylene
Chloride	274
Table 3-8. Selected Effect Estimates for Epidemiological Studies of Lung Cancers	275
Table 3-9. Summary of Significantly Increased Lung Tumor Incidences in Inhalation Studies of
Methylene Chloride	275
Table 3-10. Selected Effect Estimates for Epidemiological Studies of Breast Cancers	277
Table 3-11. Summary of Significantly Increased Mammary Tumor Incidences in Inhalation Studies of
Methylene Chloride	277
Table 3-12. Selected Effect Estimates for Epidemiological Studies of Hematopoietic Cancers	279
Table 3-13. Summary of Mononuclear Cell Leukemia Incidences in Inhalation Studies of Methylene
Chloride	280
Table 3-14. Selected Effect Estimates for Epidemiological Studies of Brain and CNS Cancers	281
Table 3-15. Candidate Non-Cancer Liver Effects for Dose-Response Modeling	297
Table 3-16. Candidate Tumor Data for Dose-Response Modeling	299
Table 3-17. Conversion of Acute PODs for Different Exposure Durations	302
Table 3-18. Results of BMD Modeling of Internal Doses Associated with Liver Lesions in Female Rates
from Nitschke et al. (1988a)	305
Table 3-19. BMD Modeling Results and HECs Determined for 10% Extra Risk, Liver Endpoints from
Two Studies	306
Table 3-20. BMD Modeling Results and Tumor Risk Factors/HECs Determined for 10% Extra Risk,
Various Endpoints From Aiso et al. (2014a) and NTP (1986)	 309
Table 3-21. Summary of PODs for Evaluating Human Health Hazards from Acute and Chronic
Inhalation Scenarios	313
Table 3-22. Summary of PODs for Evaluating Human Health Hazards from Acute and Chronic Dermal
Exposure Scenarios	313
Table 4-1. Final Summary of Facilities Showing Risk from Acute and/or Chronic Exposure from the
Release of Methylene Chloride; RQ Greater Than One are Shown in Bold	316
Page 16 of 753

-------
Table 4-2 Summary of Risk Estimates for Inhalation and Dermal Exposures to Workers by Condition of
Use	319
Table 4-3 Summary of Risk Estimates for CNS effects from Acute Inhalation and Dermal Exposures to
Consumers by Conditions of Use	334
Table 4-4. Modeled Facilities Showing Risk from Acute and/or Chronic Exposure from the Release of
Methylene Chloride; RQ Greater Than One are Shown in Bold	349
Table 4-5. RQs Calculated using Monitored Environmental Concentrations from WQP	352
Table 4-6. Use Scenarios, Populations of Interest and Toxicological Endpoints for Assessing
Occupational Risks Following Acute Exposures to Methylene Chloride	361
Table 4-7. Use Scenarios, Populations of Interest and Toxicological Endpoints for Assessing Consumer
Risks Following Acute Exposures to Methylene Chloride	362
Table 4-8. Use Scenarios, Populations of Interest and Toxicological Endpoints for Assessing
Occupational Risks Following Chronic Exposures to Methylene Chloride	363
Table 4-9. Inhalation Exposure Data Summary and Respirator Use Determination	366
Table 4-10. Risk Estimation for Acute, Non-Cancer Inhalation Exposures for Manufacturing	370
Table 4-11. Risk Estimation for Chronic, Non-Cancer Inhalation Exposures for Manufacturing	371
Table 4-12. Risk Estimation for Chronic, Cancer Inhalation Exposures for Manufacturing	371
Table 4-13. Risk Estimation for Acute, Non-Cancer Inhalation Exposures for Processing as a Reactant
	372
Table 4-14. Risk Estimation for Chronic, Non-Cancer Inhalation Exposures for Processing as a Reactant
	373
Table 4-15. Risk Estimation for Chronic, Cancer Inhalation Exposures for Processing as a Reactant.. 373
Table 4-16. Risk Estimation for Acute, Non-Cancer Inhalation Exposures for Processing - Incorporation
into Formulation, Mixture, or Reaction Product	374
Table 4-17. Risk Estimation for Chronic, Non-Cancer Inhalation Exposures for Processing -
Incorporation into Formulation, Mixture, or Reaction Product	374
Table 4-18. Risk Estimation for Chronic, Cancer Inhalation Exposures for Processing - Incorporation
into Formulation, Mixture, or Reaction Product	375
Table 4-19. Risk Estimation for Acute, Non-Cancer Inhalation Exposures for Repackaging	375
Table 4-20. Risk Estimation for Chronic, Non-Cancer Inhalation Exposures for Repackaging	376
Table 4-21. Risk Estimation for Chronic, Cancer Inhalation Exposures for Repackaging	376
Table 4-22. Risk Estimation for Acute, Non-Cancer Inhalation Exposures for Waste Handling, Disposal,
Treatment, and Recycling	377
Table 4-23. Risk Estimation for Chronic, Non-Cancer Inhalation Exposures for Waste Handling,
Disposal, Treatment, and Recycling	377
Table 4-24. Risk Estimation for Chronic, Cancer Inhalation Exposures for Waste Handling, Disposal,
Treatment, and Recycling	378
Table 4-25. Risk Estimation for Acute, Non-Cancer Inhalation Exposures for Batch Open-Top Vapor
Degreasing	378
Table 4-26. Risk Estimation for Chronic, Non-Cancer Inhalation Exposures for Batch Open-Top Vapor
Degreasing	379
Table 4-27. Risk Estimation for Chronic, Cancer Inhalation Exposures for Batch Open-Top Vapor
Degreasing	379
Table 4-28. Risk Estimation for Acute, Non-Cancer Inhalation Exposures for Conveyorized Vapor
Degreasing	380
Table 4-29. Risk Estimation for Chronic, Non-Cancer Inhalation Exposures for Convey orized Vapor
Degreasing	380
Table 4-30. Risk Estimation for Chronic, Cancer Inhalation Exposures for Convey orized Vapor
Degreasing	380
Page 17 of 753

-------
Table 4-31. Risk Estimation for Acute, Non-Cancer Inhalation Exposures for Cold Cleaning	381
Table 4-32. Risk Estimation for Chronic, Non-Cancer Inhalation Exposures for Cold Cleaning	381
Table 4-33. Risk Estimation for Chronic, Cancer Inhalation Exposures for Cold Cleaning	382
Table 4-34. Risk Estimation for Acute, Non-Cancer Inhalation Exposures for Commercial Aerosol
Products (Aerosol Degreasing, Aerosol Lubricants, Automotive Care Products)	382
Table 4-35. Risk Estimation for Chronic, Non-Cancer Inhalation Exposures for Commercial Aerosol
Products (Aerosol Degreasing, Aerosol Lubricants, Automotive Care Products)	383
Table 4-36. Risk Estimation for Chronic, Cancer Inhalation Exposures for Commercial Aerosol Products
(Aerosol Degreasing, Aerosol Lubricants, Automotive Care Products)	383
Table 4-37. Risk Estimation for Acute, Non-Cancer Inhalation Exposures for Adhesives and Sealants
	384
Table 4-38. Risk Estimation for Chronic, Non-Cancer Inhalation Exposures for Adhesives and Sealants
	385
Table 4-39. Risk Estimation for Chronic, Cancer Inhalation Exposures for Adhesives and Sealants ... 385
Table 4-40. Risk Estimation for Acute, Non-Cancer Inhalation Exposures for Paints and Coatings
Including Commercial Paint and Coating Removers	386
Table 4-41. Risk Estimation for Chronic, Non-Cancer Inhalation Exposures for Paints and Coatings. 388
Table 4-42. Risk Estimation for Chronic, Cancer Inhalation Exposures for Paints and Coatings	389
Table 4-43. Risk Estimation for Acute, Non-Cancer Inhalation Exposures for Adhesive and Caulk
Removers	391
Table 4-44. Risk Estimation for Chronic, Non-Cancer Inhalation Exposures for Adhesive and Caulk
Removers	391
Table 4-45. Risk Estimation for Chronic, Cancer Inhalation Exposures for Adhesive and Caulk
Removers	392
Table 4-46. Risk Estimation for Acute, Non-Cancer Inhalation Exposures for Non-Aerosol Commercial
and Industrial Uses	393
Table 4-47. Risk Estimation for Chronic, Non-Cancer Inhalation Exposures for Non-Aerosol
Commercial and Industrial Uses	393
Table 4-48. Risk Estimation for Chronic, Cancer Inhalation Exposures for Non-Aerosol Commercial and
Industrial Uses	393
Table 4-49. Risk Estimation for Acute, Non-Cancer Inhalation Exposures for Fabric Finishing	394
Table 4-50. Risk Estimation for Chronic, Non-Cancer Inhalation Exposures for Fabric Finishing	394
Table 4-51. Risk Estimation for Chronic, Cancer Inhalation Exposures for Fabric Finishing	395
Table 4-52. Risk Estimation for Acute, Non-Cancer Inhalation Exposures for Spot Cleaning	395
Table 4-53. Risk Estimation for Chronic, Non-Cancer Inhalation Exposures for Spot Cleaning	396
Table 4-54. Risk Estimation for Chronic, Cancer Inhalation Exposures for Spot Cleaning	396
Table 4-55. Risk Estimation for Acute, Non-Cancer Inhalation Exposures for Cellulose Triacetate Film
Production	397
Table 4-56. Risk Estimation for Chronic, Non-Cancer Inhalation Exposures for Cellulose Triacetate
Film Production	397
Table 4-57. Risk Estimation for Chronic, Cancer Inhalation Exposures for Cellulose Triacetate Film
Production	397
Table 4-58. Risk Estimation for Acute, Non-Cancer Inhalation Exposures for Plastic Product
Manufacturing	398
Table 4-59. Risk Estimation for Chronic, Non-Cancer Inhalation Exposures for Plastic Product
Manufacturing	399
Table 4-60. Risk Estimation for Chronic, Cancer Inhalation Exposures for Plastic Product
Manufacturing	399
Page 18 of 753

-------
Table 4-61.
Table 4-62.
Table 4-63.
Table 4-64.
Table 4-65.
Table 4-66.
Table 4-67.
Table 4-68.
Table 4-69.
Table 4-70.
Table 4-71.
Table 4-72.
Table 4-73.
Table 4-74.
Table 4-75.
Table 4-76.
Table 4-77.
Table 4-78.
Table 4-79.
Table 4-80.
Table 4-81.
Table 4-82.
Table 4-83.
Table 4-84.
Table 4-85.
Table 4-86.
Table 4-87.
Table 4-88.
Table 4-89.
Table 4-90.
Table 4-91.
Table 4-92.
Table 4-93.
Risk Estimation for Acute, Non-Cancer Inhalation Exposures for Flexible Polyurethane
Foam Manufacturing	400
Risk Estimation for Chronic, Non-Cancer Inhalation Exposures for Flexible Polyurethane
Foam Manufacturing	400
Risk Estimation for Chronic, Cancer Inhalation Exposures for Flexible Polyurethane Foam
Manufacturing	400
Risk Estimation for Acute, Non-Cancer Inhalation Exposures for Laboratory Use	401
Risk Estimation for Chronic, Non-Cancer Inhalation Exposures for Laboratory Use	402
Risk Estimation for Chronic, Cancer Inhalation Exposures for Laboratory Use	402
Risk Estimation for Acute, Non-Cancer Inhalation Exposures for Lithographic Printing Plate
Cleaning	403
Risk Estimation for Chronic, Non-Cancer Inhalation Exposures for Lithographic Printing
Plate Cleaning	403
Risk Estimation for Chronic, Cancer Inhalation Exposures for Lithographic Printing Plate
Cleaning	403
MOEs for Acute Dermal Exposures to Workers, by Occupational Exposure Scenario for
CNS Effects POD 16 mg/kg/day, Benchmark MOE 30	404
MOEs for Chronic Dermal Exposures to Workers, by Occupational Exposure Scenario for
Liver Effects POD 2.15 mg/kg/day, Benchmark MOE = 10	406
Cancer Risk for Chronic Dermal Exposures to Workers, by Occupational Exposure Scenario
CSF 1.1 x 10"5 per mg/kg/day	408
Risk Estimation for Acute, Non-Cancer Inhalation Exposures for Brake Cleaner Use	411
Risk Estimation for Acute, Non-Cancer Dermal Exposures for Brake Cleaner Use	411
Risk Estimation for Acute, Non-Cancer Inhalation Exposures for Carbon Remover Use . 412
Risk Estimation for Acute, Non-Cancer Dermal Exposures for Carbon Remover Use	412
Risk Estimation for Acute, Non-Cancer Inhalation Exposures for Carburetor Cleaner Use
	413
Risk Estimation for Acute, Non-Cancer
Risk Estimation for Acute, Non-Cancer
Risk Estimation for Acute, Non-Cancer
Risk Estimation for Acute, Non-Cancer
Risk
Risk
Risk
Risk
Risk
Risk
Risk
Risk
Risk
Risk
Risk
Risk
Table 4-94
Table 4-95
Risk Esti
Risk Esti
mati
mati
Dermal Exposures for Carburetor Cleaner Use .. 414
Inhalation Exposures for Coil Cleaner Use	414
Dermal Exposures for Coil Cleaner Use	415
Inhalation Exposures for Electronics Cleaner Use
	416
Estimation for Acute, Non-Cancer
Estimation for Acute, Non-Cancer
Estimation for Acute, Non-Cancer
Estimation for Acute, Non-Cancer
Estimation for Acute, Non-Cancer
Estimation for Acute, Non-Cancer
Estimation for Acute, Non-Cancer
Estimation for Acute, Non-Cancer
Estimation for Acute, Non-Cancer
Estimation for Acute, Non-Cancer
Estimation for Acute, Non-Cancer
Estimation for Acute, Non-Cancer
Dermal Exposures for Electronics Cleaner Use.. 416
Inhalation Exposures for Engine Cleaner Use .... 417
Dermal Exposures for Engine Cleaner Use	417
Inhalation Exposures for Gasket Remover Use ..418
Dermal Exposures for Gasket Remover Use	418
Inhalation Exposures for Adhesives Use	419
Dermal Exposures for Adhesives Use	420
Inhalation Exposures for Auto Leak Sealer Use. 420
Dermal Exposures for Auto Leak Sealer Use	421
Inhalation Exposures for Brush Cleaner Use	422
Dermal Exposures for Brush Cleaner Use	422
Inhalation Exposures for Adhesive Remover Use
	423
on for Acute, Non-
on for Acute, Non-
Cancer Dermal Exposures for Adhesive Remover Use .. 423
Cancer Inhalation Exposures for Auto AC Refrigerant Use
	424
Table 4-96. Risk Estimation for Acute, Non-Cancer Dermal Exposures for Auto AC Refrigerant Use 424
Page 19 of 753

-------
Table 4-97. Risk Estimation for Acute, Non-Cancer Inhalation Exposures for Cold Pipe Insulation Spray
Use	425
Table 4-98. Risk Estimation for Acute, Non-Cancer Dermal Exposures for Cold Pipe Insulation Spray
Use	425
Table 4-99. Risk Estimation for Acute, Non-Cancer Inhalation Exposures for Sealants Use	426
Table 4-100. Risk Estimation for Acute, Non-Cancer Dermal Exposures for Sealants Use	426
Table 4-101. Risk Estimation for Acute, Non-Cancer Inhalation Exposures for Weld Spatter Protectant
Use	427
Table 4-102. Risk Estimation for Acute, Non-Cancer Dermal Exposures for Weld Spatter Protectant Use
	428
Table 4-103 Table of Occupational Exposure Assessment Approach for Inhalation	432
LIST OF FIGURES
Figure 1-1. Methylene Chloride Life Cycle Diagram	48
Figure 1-2. Methylene Chloride Conceptual Model for Industrial and Commercial Activities and Uses:
Potential Exposure and Hazards	64
Figure 1-3. Methylene Chloride Conceptual Model for Consumer Activities and Uses: Potential
Exposure and Hazards	65
Figure 1-4. Methylene Chloride Conceptual Model for Environmental Releases and Wastes: Potential
Exposures and Hazards	66
Figure 1-5. Literature Flow Diagram for Environmental Fate and Transport Data Sources	69
Figure 1-6. Releases and Occupational Exposures Literature Flow Diagram for Methylene Chloride... 70
Figure 1-7. Literature Flow Diagram for General Population, Consumer and Environmental Exposure
Data Sources	71
Figure 1-8. Literature Flow Diagram for Environmental Hazard Data Sources	72
Figure 1-9. Literature Flow Diagram for Human Health Hazard Data Sources	73
Figure 2-1 Environmental transport, partitioning, and degradation processes for methylene chloride.... 77
Figure 2-2. Surface Water Concentrations of Methylene Chloride from Releasing Facilities (Maximum
Days of Release Scenario) and Water Quality Exchange (WQX) Monitoring Stations:
Year 2016, Eastern U.S	105
Figure 2-3. Surface Water Concentrations of Methylene Chloride from Releasing Facilities (Maximum
Days of Release Scenario) and Water Quality Exchange (WQX) Monitoring Stations:
Year 2016, Western U.S	106
Figure 2-4. Concentrations of Methylene Chloride from Releasing Facilities (20 Days of Release
Scenario) and Water Quality Exchange (WQX)Monitoring Stations: Year 2016, East U.S.
	107
Figure 2-5. Concentrations of Methylene Chloride from Releasing Facilities (20 Days of Release
Scenario) and Water Quality Exchange (WQX) Monitoring Stations: Year 2016, West
U.S	108
Figure 2-6. Co-location of Methylene Chloride Releasing Facilities and Water Quality Exchange
(WQX) Monitoring Stations at the HUC 8 and HUC 12 Level	110
Figure 2-7. Search of CDR, DMR (NPDES), Superfund, and TRI facilities in 2016 within HUC-8 of
Water Quality Portal (WQP) Station 21NC03WQ-AMS20161206 -B8484000	 112
Figure 2-8. Search of CDR, NPDES, Superfund, and TRI facilities in 2016 within HUC-8 of Water
Quality Portal (WQP) Stations 21NC03WQ-E1485000 and 21NC03WQ-E3475000... 113
Figure 3-1. EPA Approach to Hazard Identification, Data Integration, and Dose-Response Analysis for
Methylene Chloride	240
Figure 3-2. Biotransformation Scheme of Methylene Chloride (modified after Gargas et al., 1986).... 245
Page 20 of 753

-------
Figure 4-1. Surface Water Concentrations of Methylene Chloride from Releasing Facilities (Maximum
Days of Release Scenario) and WQX Monitoring Stations: Year 2016, East U.S	354
Figure 4-2. Surface Water Concentrations of Methylene Chloride from Releasing Facilities (Maximum
Days of Release Scenario) and WQX Monitoring Stations: Year 2016, West U.S	355
Figure 4-3. Concentrations of Methylene Chloride from Releasing Facilities (20 Days of Release
Scenario) and WQX Monitoring Stations: Year 2016, East U.S	356
Figure 4-4. Concentrations of Methylene Chloride from Methylene Chloride-Releasing Facilities (20
Days of Release Scenario) and WQX Monitoring Stations: Year 2016, West U.S	357
Figure 4-5. Co-location of Methylene Chloride Releasing Facilities and WQX Monitoring Stations at the
IILC 8 and HUC 12 Level	358
LIST OF APPENDIX TABLES
Table_Apx A-l. Federal Laws and Regulations	551
Table_Apx A-2. State Laws and Regulations	561
Table_Apx A-3. Regulatory Actions by other Governments and Tribes	563
TableApx D-l. Water Releases Reported in 2016 TRI or DMR for Occupational Exposure Scenarios
	568
Table Apx E-l. Occurrence of Methylene Dichloride Releases (Facilities) and Monitoring Sites By
HUC-8	573
Table Apx E-2. Occurrence of Methylene Dichloride Releases (Facilities) and Monitoring Sites By
I ILC-12	578
Table Apx E-3. Sample Information for WQX Surface Water Observations With Concentrations Above
the Reported Detection Limit: 2013-2017a	585
Table Apx E-4. E-FAST Modeling Results for Known Direct and Indirect Releasing Facilities for 2016
	588
Table_Apx E-5. States with Monitoring Sites or Facilities in 2016	 606
Table Apx F-l. Respirator Specifications by APF for Use in Paint and Coating Removal Scenarios with
Methylene Chloride Exposure	607
Table_Apx F-2. Glove Types Evaluated for Pure Methylene Chloride	609
Table Apx F-3. Recommended Glove Materials Methylene Chloride and Methylene Chloride-
Containing Products from SDSs	615
Table Apx G-G-l. Example Structure of CEM Cases Modeled for Each consumer Product Use
Scenario	617
Table Apx H-l. Aquatic Toxicity Data Extraction Table for Methylene Chloride	631
Table Apx H-2. Risk Quotients for All Facilities Modeled in E-FAST	645
Table Apx J-l. Fatalities That Have Associated Exposure Concentrations	687
Table Apx K-l Methylene Chloride Genotoxicity Studies not Cited in the 2011 IRIS Assessment.... 692
Table Apx K-2 Results from in vitro Genotoxicity Assays of Dichloromethane in Nonmammalian
Systems	697
TableApx K-3 Results from in vitro Genotoxicity Assays of Dichlorom ethane with Mammalian
Systems, by Type of Test	699
Table Apx K-4 Results from in vivo Genotoxicity Assays of Dichloromethane in Insects	702
Table Apx K-5 Results from in vivo Genotoxicity Assays of Dichloromethane in Mice	703
Table Apx K-6 Results from in vivo Genotoxicity Assays of Dichloromethane in Rats and Hamsters 705
Table Apx K-7 Comparison of in vivo Dichloromethane Genotoxicity Assays Targeted to Lung or Liver
Cells, by Species	706
Table Apx L-l. Raw Air Sampling Data for Methylene Chloride During DoD Uses in Paint and Coating
Removers	708
Page 21 of 753

-------
TableApx L-2. Acute and Chronic Exposures for Methylene Chloride During DoD Uses in Paint and
Coating Removers	708
Table Apx L-3. Summary of Dermal Exposure Doses to Methylene Chloride for Paint and Coatings
Removal Uses	709
Table Apx M-l. Synthesis of Epidemiological Evidence	748
Table_Apx M-2. Synthesis of Animal Evidence	749
Table_Apx M-3. Synthesis of Mechanistic Evidence	750
Table Apx M-4. Evidence Integration Summary Judgment: Immunotoxicity	752
LIST OF APPENDIX FIGURES
FigureApx C-l. EPI Suite Model Inputs for Estimating Methylene Chloride Fate and Transport
Properties	567
Figure Apx 1-1. Process of Deriving the Cancer Inhalation Unit Risk for Methylene Chloride	684
Page 22 of 753

-------
ACKNOWLEDGEMENTS
This report was developed by the United States Environmental Protection Agency (U.S. EPA), Office of
Chemical Safety and Pollution Prevention (OCSPP), Office of Pollution Prevention and Toxics (OPPT).
Acknowledgements
The OPPT Assessment Team gratefully acknowledges participation and/or input from Intra-agency
reviewers that included multiple offices within EPA, Inter-agency reviewers that included multiple
Federal agencies, and assistance from EPA contractors GDIT (Contract No. CIO-SP3,
HHSN316201200013W), ERG (Contract No. EP-W-12-006), Versar (Contract No. EP-W-17-006), ICF
(Contract No. EPC14001) and SRC (Contract No. EP-W-12-003).
Docket
Supporting information can be found in public docket: EPA-HQ-QPPT-2016	0742.
Disclaimer
Reference herein to any specific commercial products, process or service by trade name, trademark,
manufacturer or otherwise does not constitute or imply its endorsement, recommendation or favoring by
the United States Government.
Authors
Stan Barone (Deputy Division Director), Yvette Selby-Mohamadu (Management Lead), Chris
Brinkerhoff (Staff Lead), Kara Koehrn (Staff Lead), Marcy Card, Jason Todd, Giorvanni Merilis, Tracy
Wright, Amy Benson, Scott Prothero, Nicholas Suek, Ana Corado, Ingrid Feustel, Judith Brown, Daniel
DePasquale, Paul Schlosser, Michael Wright, Tom Bateson, Amanda Persad, Jeff Gift, Suryanarayana
Vulimiri, Channa Keshava, Nagalakshmi Keshava, Audrey Galizia, Paul White, Allen Davis, Dustin
Kapraun, Lily Wang
Page 23 of 753

-------
ABBREVIATIONS
c
Degrees Celsius
ACGM
American Conference of Government Industrial Hygienists
ACh
Acetylcholine
ACR
Acute-to-chronic Ratio
ADC
Average Daily Concentration
ADR
Acute Dose Rate
AEGL
Acute Exposure Guideline Level
AF
Assessment Factor
AhR
Aryl Hydrocarbon Receptor
AIC
Akaike information criterion
ALT
Alanine Transaminase
ANOVA
Analysis of Variance
APF
Assigned Protection Factor
ASD
Autism Spectrum Disorder
AST
Aspartate Amino Transferase
atm
Atmosphere(s)
ATSDR
Agency for Toxic Substances and Disease Registry
BAF
Bioaccumulation Factor
BCF
Bioconcentration Factor
BCFBAF
EPI Suite model that estimates Bioconcentration and Bioaccumulation Factors
BIOWIN
EPI Suite model that estimates Biodegradation rates
BMD
Benchmark Dose
BMDL
Benchmark Dose Lower Confidence Limit
BMR
Benchmark Response
BMDS
Benchmark Dose Software
CAA
Clean Air Act
CADD
Chronic Average Daily Dose
CAR
Constitutive Androstane Receptor
CASRN
Chemical Abstracts Service Registry Number
CARB
California Air Resources Board
CBI
Confidential Business Information
CDR
Chemical Data Reporting
CEM
Consumer Exposure Model
CEPA
Canadian Environmental Protection Act
CERCLA
Comprehensive Environmental Response, Compensation and Liability Act
CFF
Critical Flicker Function
CFR
Code of Federal Regulations
CHIRP
Chemical Risk Information Platform
ChV
Chronic Value
CI
Confidence Interval
cm3
Cubic Centimeter(s)
CNS
Central Nervous System
coc
Concentration of Concern
CoCAP
Cooperative Chemicals Assessment Program
COHb
Carboxyhemoglobin
COU
Conditions of Use
CPDat
Chemical and Products Database
Page 24 of 753

-------
CPSC
Consumer Product Safety Commission
CSCL
Chemical Substances Control Law
CWA
Clean Water Act
CYP450
Cytochrome P450
DCM
Dichloromethane (Methylene Chloride)
DF
Dilution Factor
DFq
Detection frequency
DMR
Discharge Monitoring Report
DNA
Deoxyribonucleic Acid
DoD
Department of Defense
EC50
Effect concentration at which 50% of test organisms exhibit an effect
ECHA
European Chemicals Agency
ECHO
Enforcement and Compliance History Online
ECOTOX
ECOTOXicology Knowledgebase System
EEG
El ectroencephal ogram
EF
Exposure Frequency
E-FAST
Exposure and Fate Assessment Screening Tool
ELCR
Excess Lifetime Cancer Risk
EPA
Environmental Protection Agency
EPCRA
Emergency Planning and Community Right-to-Know Act
EPI Suite
Estimation Programs Interface suite of models
ER
Extra Risk
EU
European Union
EVOH
Ethylene Vinyl Alcohol
FACE
Fatality Assessment and Control Evaluation
FDA
Food and Drug Administration
FFDCA
Federal Food, Drug, and Cosmetic Act
FR
Federal Register
FRSID
Facility Registry Service Identification
g
Gram(s)
GABA
Gamma-aminobutyric Acid
GC
Gas Chromatography
GD(s)
Gestational Day
GM
Geometric Mean
GSD
Geometric Standard Deviation
GSH
Glutathione
GST
Glutathione S-transferase
GSTT1
Theta 1 Isozyme
HAP
Hazardous Air Pollutant
HEC
Human Equivalent Concentration(s)
HED
Human Equivalent Dose(s)
HEDD
Human Equivalent Dermal Dose
HFC
Hydrofluorocarbon
HHE
Health Hazard Evaluation
HMTA
Hazardous Materials Transportation Act
Hr
Hour(s)
HR
Hazard Ratio
HSE
Health and Safety Executive
HSIA
Halogenated Solvents Industry Alliance
Page 25 of 753

-------
HUC
Hydrologic Unit Code
i arc:
International Agency for Research on Cancer
icis
Integrated Compliance Information System
IDLH
Immediately Dangerous to Life or Health
IH
Industrial Hygiene
IMAP
Inventory Multi-Tiered Assessment and Prioritisation
IPCS
International Programme on Chemical Safety
IRIS
Integrated Risk Information System
IRR
Incidence rate ratios
ISHA
Industrial Safety and Health Act
IUR
Inhalation Unit Risk
Koc
Soil Organic Carbon-Water Partitioning Coefficient
Kow
Octanol/Water Partition Coefficient
kg
Kilogram(s)
L
Liter(s)
LADC
Lifetime Average Daily Concentration
lb
Pound(s)
LC50
Lethal Concentration at which 50% of test organisms die
LCL
Lower confidence limit
LOAEC
Lowest Observed Adverse Effect Concentration
LOAEL
Lowest Observed Adverse Effect Level
LOD
Limit of Detection
LOEC
Lowest Observable Effect Concentration
Log Koc
Logarithmic Organic Carbon:Water Partition Coefficient
Log Kow
Logarithmic Octanol: Water Partition Coefficient
3
m
Cubic Meter(s)
MACT
Maximum Achievable Control Technology
MCL
Maximum Contaminant Level
MCLG
Maximum Contaminant Level Goal
MFO
Mixed Function Oxidase
mg
Milligram(s)
Min
Minute(s)
MLD
Millions of Liters per Day
mmHg
Millimeter(s) of Mercury
MOA
Mode of Action
MOE
Margin of Exposure
mPas
Millipascal(s)-Second
MSDS
Material Safety Data Sheet
MSW
Municipal Solid Waste
N/A
Not Applicable
NAC
National Advisory Committee
NAICS
North American Industry Classification System
NATA
National Air Toxics Assessment
NAWQA
National Water Quality Assessment Program
ND
Not Detected
NEI
National Emissions Inventory
NESHAP
National Emission Standards for Hazardous Air Pollutants
NHANES
National Health and Nutrition Examination Survey
NHL
Non-Hodgkin Lymphoma
Page 26 of 753

-------
NICNAS
National Industrial Chemicals Notification and Assessment Scheme
NIH
National Institutes of Health
NIOSH
National Institute for Occupational Safety and Health
NITE
National Institute of Technology and Evaluation
NMDA
N-Methyl-D-Aspartate
NMP
N-Methylpyrrolidone
NO
Nitric Oxide
NOAEL
No Observed Adverse Effect Level
NOEC
No Observed Effect Concentration
NPDES
National Pollutant Discharge Elimination System
NPDWR
National Primary Drinking Water Regulation
NPL
National Priority List
NRC
National Research Council
NT
Not tested
NTP
National Toxicology Program
NWIS
National Water Information System
OCSPP
Office of Chemical Safety and Pollution Prevention
OECD
Organisation for Economic Co-operation and Development
OEHHA
Office of Environmental Health Hazard Assessment
OEL
Occupational Exposure Limit
OES
Occupational Exposure Scenario
ONU
Occupational Non-User
OPPT
Office of Pollution Prevention and Toxics
OR
Odds Ratio
ORD
Office of Research and Development
OSHA
Occupational Safety and Health Administration
OTVD
Open-Top Vapor Degreaser
OW
Office of Water
PAH
Polycyclic Aromatic Hydrocarbons
PBMC
Peripheral Blood Mononuclear Cells
PBPK
Physiologically-Based Pharmacokinetic
PBPK/PD
Physiologically-Based Pharmacokinetic/Pharmacodynamic
PDM
Probabilistic Dilution Model
PE
Polyethylene
PECO
Population, Exposure, Comparator, and Outcome
PEL
Permissible Exposure Limit
PESS
Potentially Exposed or Susceptible Subpopulations
PF
Protection Factor
POD
Point of Departure
POTW
Publicly Owned Treatment Works
ppb
Part(s) per Billion
PPE
Personal Protective Equipment
ppm
Part(s) per Million
PVA
Polyvinyl Alcohol
PXR
Pregnane X Receptor
QC
Quality Control
QSAR
Quantitative Structure-Activity Relationships
RBC
Red blood cell
RCRA
Resource Conservation and Recovery Act
Page 27 of 753

-------
RD	Relative Deviation
REACH	Registration, Evaluation, Authorisation and Restriction of Chemicals
REL	Reference Exposure Level for California EPA OEHHA
RfC	Reference Concentration
RfD	Reference Dose
RICE	Reciprocating Internal Combustion Engines
ROS	Reactive Oxygen Species
RQ	Risk Quotient
RTR	Risk and Technology Review
SAR	Supplied Air Respirator
SCB A	Self-Contained Breathing Apparatus
SD	Standard Deviation
SDH	Succinate Dehydrogenase
SDS	Safety Data Sheets
SDWA	Safe Drinking Water Act
SEMS	Superfund Enterprise Management System
SIC	Standard Industrial Classification
SIDS	Screening Information Data Set
SIR	Standard Incidence Rate
SMAC	Spacecraft Maximum Allowable Concentrations
SMR	Standardized Mortality Ratio
SNAP	Significant New Alternatives Policy
SpERC	Specific Environmental Release Categories
STEL	Short-Term Exposure Limit
STEWARDS Sustaining the Earth's Watersheds - Agricultural Research Database System
STORET	STOrage and RETrieval database
STPWIN	EPI Suite model of chemical removal in Sewage Treatment Plants
SVOC	Semivolatile Organic Compounds
SWC	Surface Water Concentration
TLV	Threshold Limit Value
TNO	The Netherlands Organisation for Applied Scientific Research
TRI	Toxics Release Inventory
TSCA	Toxic Substances Control Act
TSDF	Treatment, Storage, and Disposal Facility
TTO	Total Toxic Organics
TWA	Time-Weighted Average
UCL	Upper confidence limit
UF	Uncertainty Factor
UFa	Interspecies Uncertainty/Variability Factor
UFh	Interspecies Uncertainty Factor
UFl	LOAEL-to-NOAEL Uncertainty Factor
U.K.	United Kingdom
U.S.	United States
U.S.C.	United States Code
USGS	United States Geological Survey
VOC	Volatile Organic Compound
VER	Visual Evoked Response
WHO	World Health Organization
wk	Week
Page 28 of 753

-------
WQP	Water Quality Portal
WQX	Water Quality Exchange
WY	Exposed Working Years per Lifetime
Yr	Year(s)
Page 29 of 753

-------
EXECUTIVE SUMMARY
This risk evaluation for methylene chloride was performed in accordance with the Frank R. Lautenberg
Chemical Safety for the 21st Century Act and is being issued following public comment and peer
review. The Frank R. Lautenberg Chemical Safety for the 21st Century Act amended the Toxic
Substances Control Act (TSCA), the Nation's primary chemicals management law, in June 2016.
Under the amended statute, EPA is required, under TSCA  6(b), to conduct risk evaluations to
determine whether a chemical substance presents unreasonable risk of injury to health or the
environment, under the conditions of use, without consideration of costs or other non-risk factors,
including an unreasonable risk to potentially exposed or susceptible subpopulations, identified as
relevant to the risk evaluation. Also, as required by TSCA  (6)(b), EPA established, by rule, a process
to conduct these risk evaluations. Procedures for Chemical Risk Evaluation Under the Amended Toxic
Substances Control Act (82 FR 3372.6). (Risk Evaluation Rule). This risk evaluation is in conformance
with TSCA  6(b), and the Risk Evaluation Rule, and is to be used to inform risk management
decisions. In accordance with TSCA section 6(b), if EPA finds unreasonable risk from a chemical
substance under its conditions of use in any final risk evaluation, the Agency will propose actions to
address those risks within the timeframe required by TSCA. However, any proposed or final
determination that a chemical substance presents unreasonable risk under TSCA section 6(b) is not the
same as a finding that a chemical substance is "imminently hazardous" under TSCA section 7. The
conclusions, findings, and determinations in this final risk evaluation are for the purpose of identifying
whether the chemical substance presents unreasonable risk or no unreasonable risk under the
conditions of use, in accordance with TSCA Section 6, and are not intended to represent any findings
under TSCA Section 7.
TSCA  26(h) and (i) require EPA, when conducting risk evaluations, to use scientific information,
technical procedures, measures, methods, protocols, methodologies and models consistent with the
best available science and to base its decisions on the weight of the scientific evidence.1 To meet these
TSCA  26 science standards, EPA used the TSCA systematic review process described in the
Application of Systematic Review in TSCA Risk Evaluations document (	018a). The data
collection, evaluation, and integration stages of the systematic review process are used to develop the
exposure, fate, and hazard assessments for risk evaluations.
Methylene chloride has a wide range of uses, including as a solvent, propellent, processing aid, or
functional fluid in the manufacturing of other chemicals. A variety of consumer and commercial
products use methylene chloride as a solvent including sealants, automotive products, and paint and
coating removers. Methylene chloride is subject to federal and state regulations and reporting
requirements. Methylene chloride has been reportable to Toxics Release Inventory (TRI) chemical under
Section 313 of the Emergency Planning and Community Right-to-Know Act (EPCRA) since 1987. It is
designated a Hazardous Air Pollutant (HAP) under the Clean Air Act (CAA), and is a hazardous
substance under the Comprehensive Environmental Response, Compensation and Liability Act
(CERCLA). It is subject to National Primary Drinking Water Regulations (NPDWR) under the Safe
Drinking Water Act (SDWA) and designated as a toxic pollutant under the Clean Water Act (CWA)
making it subject to effluent limitations. Under TSCA, EPA previously assessed the use of methylene
1 Weight of the scientific evidence means a systematic review method, applied in a manner suited to the nature of the
evidence or decision, that uses a pre-established protocol to comprehensively, objectively, transparently, and consistently
identify and evaluate each stream of evidence, including strengths, limitations, and relevance of each study and to integrate
evidence as necessary and appropriate based upon strengths, limitations, and relevance.
Page 30 of 753

-------
chloride in paint and coating removal (	). In March 2019 EPA issued a final rule, where
the Agency made the determination that the use of methylene chloride in consumer paint and coating
removal presents an unreasonable risk of injury to health due to acute human lethality (84 FR 1140). To
address this unreasonable risk, the Agency prohibited the manufacture (including import), processing,
and distribution in commerce of methylene chloride for paint and coating removal, including distribution
to and by retailers; required manufacturers (including importers), processors, and distributors, except
retailers, of methylene chloride for any use to provide downstream notification of these prohibitions; and
required recordkeeping. The final rule took effect on May 28, 2019.
Methylene chloride is currently manufactured, processed, distributed, used, and disposed of as part of
additional industrial, commercial, and consumer conditions of use. Leading applications for methylene
chloride include as a solvent in the production of pharmaceuticals and polymers, metal cleaning,
production of HFC-32, and as an ingredient in adhesives and paint removers. EPA evaluated the
following categories of conditions of use: manufacturing; processing; distribution in commerce,
industrial, commercial and consumer uses and disposal.2 The total aggregate production volume ranged
from 230 to 264 million pounds between 2012 and 2015 according to CDR (Section 1.2).
Approach
EPA used reasonably available information (defined in 40 CFR 702.33 in part as "information that
EPA possesses, or can reasonably obtain and synthesize for use in risk evaluations, considering the
deadlines . . .for completing the evaluation . . . "), in a fit-for-purpose approach, to develop a risk
evaluation that relies on the best available science and is based on the weight of the scientific evidence.
EPA used previous assessments, for example EPA's IRIS assessment, as a starting point for
identifying key and supporting studies to inform the exposure, fate, and hazard assessments. EPA also
evaluated other studies published since the publication of previous analyses. EPA reviewed reasonably
available the information and evaluated the quality of the methods and reporting of results of the
individual studies using the evaluation strategies described in Application of Systematic Review in
TSCA Risk Evaluations (U.S. EPA. 2018a). To satisfy requirements in TSCA section 26(j)(4) and 40
CFR 702.51(e), EPA has provided a list of studies considered in carrying out the risk evaluation and
the results of those studies in Appendix H, Appendix K, and several supplemental files (EPA. 2019D;
(EPA. 2019e): (EPAa_2019d); (EPA. 2.019c): (	); (	19e); (EPA. 2019r): (EPA.
2.019ir): (EPA. 2019s): (EPA. 2019t): (EPA. ,); (EPA. 2019o).
In the problem formulation, EPA identified the conditions of use within the scope of the risk evaluation
and presented three conceptual models and an analysis plan for this risk evaluation (U.S. EPA... 2018c).
These have been carried into the risk evaluation where EPA has quantitatively evaluated the risk to the
environment and human health, using both monitoring data and modeling approaches, for the
conditions of use (identified in Section 1.4.1 of this risk evaluation).3 EPA quantitatively evaluated the
risk to aquatic species from exposure to surface water where, as a result of the manufacturing,
processing, use, or disposal of methylene chloride. EPA evaluated the risk to workers, from inhalation
2	Although EPA has identified both industrial and commercial uses here for purposes of distinguishing scenarios in this
analysis, the Agency interprets the authority over "any manner or method of commercial use" under TSCA section 6(a)(5) to
reach both.
3	EPA did not identify any "legacy uses" or "associated disposals" of methylene chloride, as those terms are described in
EPA's Risk Evaluation Rule, 82 FR 33726 (July 20, 2017). Therefore, no such uses or disposals were added to the scope of
the risk evaluation for methylene chloride following the issuance of the opinion in Safer Chemicals, Healthy Families v.
EPA, 943 F.3d 397 (9th Cir. 2019).
Page 31 of 753

-------
and dermal exposures, and occupational non-users (ONUs)4, from inhalation exposures, by comparing
the estimated acute and chronic exposures to human health hazards (e.g., CNS effects, liver effects, and
liver and lung tumors). EPA also evaluated the risk to consumers, from acute inhalation and dermal
exposures, and bystanders, from inhalation exposures, by comparing the estimated exposures to acute
human health hazards.
EPA used environmental fate parameters, physical-chemical properties, modelling, and monitoring
data to assess ambient water exposure to aquatic organisms and sediment-dwelling organisms. While
methylene chloride is present in various environmental media, such as groundwater, surface water, and
air, EPA determined during problem formulation that no further analysis beyond what was presented
in the problem formulation document would be done for environmental exposure pathways in this risk
evaluation. While these exposure pathways remain in the scope of the risk evaluation, EPA found no
further analysis was necessary in the risk evaluation for sediment, soil and land-applied biosolid
pathways leading to exposure to terrestrial and aquatic organisms. Further analysis was not conducted
for biosolid, soil and sediment pathways based on a qualitative assessment of the physical-chemical
properties and fate of methylene chloride in the environment and a quantitative comparison of hazards
and exposures for aquatic and terrestrial organisms. However, exposures to aquatic organisms from
surface water, are assessed and presented in this risk evaluation and used to inform the risk
determination. These analyses are described in Sections 2.1, 2.3, and 4.1.
EPA evaluated exposures to methylene chloride in occupational and consumer settings for the
conditions of use included in the scope of the risk evaluation, listed in Section 1.4 (Scope of the
Evaluation). In occupational settings, EPA evaluated acute and chronic inhalation exposures to workers
and ONUs, and acute and chronic dermal exposures to workers. EPA used inhalation monitoring data
from literature sources that met data evaluation criteria, where reasonably available. EPA also used
modeling approaches, where reasonably available, to estimate potential inhalation exposures. Dermal
doses for workers were estimated in occupational exposure scenarios since dermal monitoring data was
not reasonably available. In consumer settings, EPA evaluated acute inhalation exposures to both
consumers and bystanders, and acute dermal exposures to consumers. Inhalation exposures and dermal
doses for consumers and bystanders in these scenarios were estimated since inhalation and dermal
monitoring data were not reasonably available. These analyses are described in Section 2.4 of this risk
evaluation.
EPA reviewed the environmental hazard data using the data quality review evaluation metrics and the
rating criteria described in the Application of Systematic Review in TSCA Risk Evaluations (U.S. EPA.
2018a). EPA concluded that methylene chloride poses a hazard to environmental aquatic receptors with
amphibians being the most sensitive taxa for both acute and chronic exposures. The results of the
environmental hazard assessment are in Section 3.1.
EPA evaluated reasonably available information for human health hazards and identified hazard
endpoints including acute and chronic toxicity for non-cancer effects and cancer. EPA used the
Framework for Human Health Risk Assessment to Inform Decision Making ( 014a) to evaluate,
extract, and integrate methylene chloride's human health hazard and dose-response information. EPA
reviewed key and supporting information from previous hazard assessments [EPA OPPT Risk
Assessment (U.S. EPA. 2014). EPA IRIS Toxicologic Review (U.S. EPA. 2011). an ATSDR
Toxicological Profile ( \ i I >!<. 2000) and ( \ I SDR. 2.010) addendum, an Interim AEGL (Nac/Aegl.
4 ONUs are workers who do not directly handle methylene chloride but perform work in an area where methylene chloride is
present.
Page 32 of 753

-------
2008b). Spacecraft Maximum Allowable Concentrations Assessment (Nrc. 1996). Report on
Carcinogens, Twelfth Edition, Dichloromethane (N	), Occupational Exposure to Methylene
Chloride (OSHA) (1997b). Acute Reference Exposure Level (REL) and Toxicity Summary for
Methylene Chloride (Oehha. 2008a) and other international assessments listed in Table 1-3], EPA also
screened and evaluated new studies that were published since these reviews (i.e., from 2011 - 2018).
EPA developed a hazard and dose-response analysis using endpoints observed in inhalation and oral
hazard studies, evaluated the weight of the scientific evidence considering EPA and National Research
Council (NRC) risk assessment guidance, and selected the points of departure (POD) for acute and
chronic non-cancer endpoints, and inhalation unit risk and cancer slope factors for cancer risk
estimates. Potential health effects of methylene chloride exposure described in the literature include
effects on the central nervous system (CNS), liver, immune system, as well as irritation/burns, and
cancer. EPA identified acute PODs for inhalation and dermal exposures based on acute CNS effects
observed in humans (Putz et at.. 1979). The chronic POD for inhalation exposures are based on a study
observing increased liver vacuolation in rats (Nitschke et at.. 1988a). EPA used a probabilistic
physiologically-based pharmacokinetic (PBPK) model for interspecies extrapolation from rats to
humans and for toxicokinetic variability among humans. EPA searched for, but did not identify,
toxicity studies by the dermal route that were adequate for dose-response assessment. Therefore, dermal
candidate values were derived by route-to-route extrapolation from the inhalation PODs mentioned
above. In accordance with U.S. EPA (EPA. 2005a) Guidelines for Carcinogen Risk Assessment,
methylene chloride is considered "likely to be carcinogenic to humans" based on sufficient evidence in
animals, limited supporting evidence in humans, and mechanistic data showing a mutagenic mode of
action (MOA) relevant to humans. EPA calculated cancer risk with a linear model using cancer slope
factors based on evidence of increased risk of cancer in mice exposed to methylene chloride through air
( \iso et al.. 2014a; NTP. 1986). The results of these analyses are described in Section 3.2.
Risk Characterization
Environmental Risk: For environmental risk, EPA utilized a risk quotient (RQ) to compare the
environmental concentration to the effect level to characterize the risk to aquatic organisms. EPA
included a quantitiative assessment describing methylene chloride exposure from surface water and
sediments. The results of the risk characterization are in Section 4.2, including a table that summarizes
the RQs for acute and chronic risks.
EPA identified expected environmental exposures for aquatic species under the conditions of use in the
scope of the risk evaluation. While the estimated releases from specific facilities result in modeled
surface water concentrations that were equal to or exceed the aquatic benchmark (RQ >1), all but two
conditions of use (recycling and disposal) had RQs < 1, indicating that exposures resulting from
environmental concentrations were less than the effect concentration, or the concentration of concern.
Details of these estimates are in Section 4.2.2.
Human Health Risks: For human health risks to workers and consumers, EPA identified potential
cancer and non-cancer human health risks. Risks from acute exposures include central nervous system
risks such as central nervous system depression and a decrease in peripheral vision, each of which can
lead to workplace accidents and which are precursors to more severe central nervous system effects
such as incapacitation, loss of consciousness, and death. For chronic exposures, EPA identified risks of
non-cancer liver effects as well as liver and lung tumors.
For workers and ONUs, EPA estimated potential cancer risk from chronic exposures to methylene
chloride using inhalation unit risk or dermal cancer slope factor values multiplied by the chronic
Page 33 of 753

-------
exposure for each COU. For workers and ONUs, EPA also estimated potential non-cancer risks
resulting from acute or chronic inhalation or dermal exposures and used a Margin of Exposure (MOE)
approach. For workers, EPA estimated risks using several occupational exposure scenarios, which
varied assumptions regarding the use of personal protective equipment (PPE) for respiratory and
dermal exposures for workers directly handling methylene chloride. More information on respiratory
and dermal protection, including EPA's approach regarding the occupational exposure scenarios for
methylene chloride, is in Section 2.4.1.
For workers, acute and chronic non-cancer risks (i.e., central nervous system effects and non-cancer
liver effects) were indicated for all conditions of use under high-end inhalation or dermal exposure
scenarios if PPE was not used. For most industrial and commercial conditions of use, cancer risks were
also identified for high-end inhalation or dermal occupational exposure scenarios if PPE was not used.
With use of PPE during relevant conditions of use, worker exposures were estimated to be reduced. This
resulted in fewer conditions of use with estimated acute, chronic non-cancer, or cancer inhalation or
dermal risks. With use of respiratory protection, cancer risks from chronic inhalation risks were not
indicated for most conditions of use. Similarly, with dermal protection, non-cancer risks from acute and
chronic exposures, and cancer risks were not indicated for most conditions of use. However, some
conditions of use continued to present non-cancer inhalation risks to workers under high end
occupational exposure scenarios even with PPE (respirators APF 25 or 50, and gloves of various
protection factors). Specifically, even with use of respirators (APF 25 or 50), acute and chronic non-
cancer risks were indicated for processing methylene chloride as part of one condition of use and for
most industrial and commercial uses of methylene chloride. EPA's estimates for worker risks for each
occupational exposure scenario are presented in Section 4.3.2.1 and summarized in Table 4-106 in
Section 4.1.2.
For ONUs, acute and chronic non-cancer risks (i.e., central nervous system effects and non-cancer liver
effects) were indicated for high-end inhalation occupational exposure scenarios for processing
methylene chloride as part of several conditions of use, and for most industrial and commercial uses of
methylene chloride. Central tendency estimates of inhalation exposures showed that while fewer
conditions of use indicated non-cancer risks to ONUs from acute or chronic exposures, under many
conditions of use, inhalation risks remained. ONUs were not assumed to be using PPE to reduce
exposures to methylene chloride used in their vicinity. ONUs are not assumed to be dermally exposed to
methylene chloride; therefore, dermal risks to ONUs were not identified. EPA's estimates for ONU risks
for each occupational exposure scenario are presented in Sections 4.3.2.1 and 4.3.2.2 and Table 4-2 in
Section 4.1.2.
For consumers and bystanders for consumer use, EPA estimated non-cancer risks resulting from acute
inhalation or dermal exposures that were modeled with a range of user intensities, described in detail
in Section 2.4.2. EPA assumed that consumers or bystanders would not use PPE and that all exposures
would be acute, rather than chronic. As explained in Section 4.3.2.3,
For consumers and bystanders, risks from acute exposure (of central nervous system effects) were
indicated for most conditions of use for consumers for medium and high intensity acute inhalation and
dermal consumer exposure scenarios. Conditions of use that indicated acute risks to consumer users
(for inhalation and dermal exposure) also indicated risks to bystanders (for inhalation exposures only).
As explained in Section 4.3.2.3, estimates of MOEs for consumers were calculated for consumers for
acute inhalation and dermal exposures, because the exposure frequencies were not considered
sufficient to cause the health effects (i.e., liver effects and liver and lung tumors) that were observed in
chronic animal studies typically defined as at least 10% of the animal's lifetime
Page 34 of 753

-------
Uncertainties: Key assumptions and uncertainties in the environmental risk estimation include the
uncertainty around modeled releases. For the human health risk estimation, key assumptions and
uncertainties are related to the estimates for ONU inhalation exposures, because monitoring data were
not reasonably available for many of the conditions of use evaluated. An additional source of
uncertainty is the inhalation to dermal route-to-route extrapolations, which is a source of uncertainty in
the dermal risk assessment for dermal cancer and non-cancer risk estimates. Similarly, for assessing
cancer risks, although EPA chose to model the combination of liver and lung tumor results from a
cancer bioassay using mice, there is uncertainty regarding the modeling of these tumor types for
humans. These and other assumptions and key sources of uncertainty are detailed in Section 4.4.
EPA's assessments, risk estimations, and risk determinations account for uncertainties throughout the
risk evaluation. EPA used reasonably available information, in a fit-for-purpose approach, to develop a
risk evaluation that relies on the best available science and is based on the weight of the scientific
evidence. For instance, systematic review was conducted to identify reasonably available information
related to MC hazards and exposures. If no applicable monitoring data were identified, exposure
scenarios were assessed using a modeling approach that requires the input of various chemical
parameters and exposure factors. When possible, default model input parameters were modified based
on chemical-specific inputs available in literature databases. The consideration of uncertainties support
the Agency's risk determinations, each of which is supported by substantial evidence, as set forth in
detail in later sections of this final risk evaluation.
Potentially Exposed Susceptible Subpopulations: TSCA  6(b)(4) requires that EPA conduct risk
evaluations to determine whether a chemical substance presents unreasonable risk under the conditions
of use, including unreasonable risk to a potentially exposed or susceptible subpopulation identified as
relevant to the risk evaluation. TSCA  3(12) defines "potentially exposed or susceptible
subpopulation " as a group of individuals within the general population identified by the Administrator
who, due to either greater susceptibility or greater exposure, may be at greater risk than the general
population of adverse health effects from exposure to a chemical substance or mixture, such as infants,
children, pregnant women, workers, or the elderly.
In developing the risk evaluation, EPA analyzed reasonably available information to ascertain whether
some human receptor groups may have greater exposure or greater susceptibility than the general
population to the hazard posed by methylene chloride. For consideration of the most highly exposed
groups, EPA considered methylene chloride exposures to be higher among workers using methylene
chloride and ONUs in the vicinity of methylene chloride use than the exposures experienced by the
general population. Additionally, variability of susceptibility to methylene chloride may be correlated
with genetic polymorphism in its metabolizing enzymes. Factors other than polymorphisms that
regulate CYP2E1 may have greater influence on the formation of COHb, a metabolic product of
methylene chloride exposure. The CYP2E1 enzyme is easily inducible by many substances, resulting
in increased metabolism. For example, alcohol drinkers may have increased CO and COHb (Nac/Aeet,
2008b). Additionally, the COHb generated from methylene chloride is expected to be additive to
COHb from other sources. Populations of particular concern are smokers who maintain significant
constant levels of COHb, persons with existing cardiovascular disease (A.TSDR. 2.000). as well as
fetuses and infants. Hemoglobin in the fetus has a higher affinity for CO than does adult hemoglobin.
Thus, the neurotoxic and cardiovascular effects may be exacerbated in fetuses and infants with higher
residual levels of fetal hemoglobin when exposed to high concentrations of methylene chloride
(OEHHA. 2.008b).
Page 35 of 753

-------
Aggregate and Sentinel Exposures Section 2605(b)(4)(F)(ii) of TSCA requires the EPA, as a part of the
risk evaluation, describe whether aggregate or sentinel exposures under the conditions of use were
considered and the basis for their consideration. The EPA has defined aggregate exposure as "the
combined exposures to an individual from a single chemical substance across multiple routes and
across multiple pathways (40 CFR  702.33)." Exposures to methylene chloride were evaluated by
inhalation and dermal routes separately. Inhalation and dermal exposures are assumed to occur
simultaneously for workers and consumers. EPA chose not to employ simple additivity of exposure
pathways at this time within a condition of use, because it would result in an overestimate of risk.
EPA defines sentinel exposure as "the exposure to a single chemical substance that represents the
plausible upper bound of exposure relative to all other exposures within a broad category of similar or
related exposures (40 CFR  702.33)." In this risk evaluation, EPA considered sentinel exposure the
highest exposure given the details of the conditions of use and the potential exposure scenarios. In terms
of this risk evaluation, EPA considered sentinel exposure the highest exposure given the details of the
conditions of use and the potential exposure scenarios. Sentinel exposures for workers are the high-end
no PPE within each OES. In cases where sentinel exposures result in MOEs greater than the benchmark
or cancer risk lower than the benchmark, EPA did no further analysis because sentinel exposures
represent the worst-case scenario.
Unreasonable Risk Determination
In each risk evaluation under TSCA section 6(b), EPA determines whether a chemical substance
presents an unreasonable risk of injury to health or the environment, under the conditions of use. The
determination does not consider costs or other non-risk factors. In making this determination, EPA
considers relevant risk-related factors, including, but not limited to: the effects of the chemical substance
on health and human exposure to such substance under the conditions of use (including cancer and non-
cancer risks); the effects of the chemical substance on the environment and environmental exposure
under the conditions of use; the population exposed (including any potentially exposed or susceptible
subpopulations, as determined by EPA); the severity of hazard (including the nature of the hazard, the
irreversibility of the hazard); and uncertainties. EPA also takes into consideration the Agency's
confidence in the data used in the risk estimate. This includes an evaluation of the strengths, limitations,
and uncertainties associated with the information used to inform the risk estimate and the risk
characterization. The rationale for the unreasonable risk determination is in section 5.2. The Agency's
risk determinations are supported by substantial evidence, as set forth in detail in later sections of this
final risk evaluation.
While use of methylene chloride as a functional fluid in a closed system during pharmaceutical
manufacturing was included in the problem formulation and draft risk evaluation, upon further analysis
of the details of this process, EPA has determined that this use falls outside TSCA's definition of
"chemical substance." Under TSCA  3(2)(B)(vi), the definition of "chemical substance" does not
include any food, food additive, drug, cosmetic, or device (as such terms are defined in section 201 of
the Federal Food, Drug, and Cosmetic Act) when manufactured, processed, or distributed in commerce
for use as a food, food additive, drug, cosmetic, or device. EPA has found that methylene chloride use
as a functional fluid in a closed system during pharmaceutical manufacturing entails use as an extraction
solvent in the purification of pharmaceutical products, and has concluded that this use falls within the
aforementioned definitional exclusion and is not a "chemical substance" under TSCA.
Unreasonable Risk of Injury to the Environment: Based on its physical-chemical properties, methylene
chloride does not partition to or accumulate in soil. Therefore, EPA determined that there is no
unreasonable risk to terrestrial organisms from all conditions of use. To characterize the exposures to
Page 36 of 753

-------
methylene chloride by aquatic organisms EPA considered modeled data to represent surface water
concentrations near facilities actively releasing methylene chloride to surface water, as well as
monitored concentrations to represent ambient water concentrations of methylene chloride. EPA
considered the biological relevance of the species to determine the concentrations of concern, as well as
frequency and duration of the exposures, and uncertainties of the limited number of data points above
the RQ. EPA determined that the evaluation does not support an unreasonable risk determination to
aquatic organisms. Similarly, EPA determined that the evaluation does not support an unreasonable risk
determination to sediment dwelling organisms, since methylene chloride is most likely present in the
pore waters and the concentrations in sediment pore water are assumed to be similar or less to the
concentrations in the overlying water.
Unreasonable Risks of Injury to Health: EPA's determination of unreasonable risk for specific
conditions of use of methylene chloride listed below are based on health risks to workers, ONUs,
consumers, or bystanders from consumer use. As described below, EPA did not evaluate unreasonable
risk to the general population in this risk evaluation. For acute exposures, EPA evaluated unreasonable
risk to the central nervous system, such as central nervous system depression and a decrease in
peripheral vision, each of which can lead to workplace accidents and which are precursors to more
severe central nervous system effects such as incapacitation, loss of consciousness, and death. For
chronic exposures, EPA evaluated unreasonable risk of non-cancer liver effects (including
vacuolization, necrosis, hemosiderosis and hepatocellular degeneration) as well as cancer (liver and lung
tumors).
Unreasonable Risk of Injury to Health of the General Population: As part of the problem formulation for
methylene chloride, EPA found that exposures to the general population may occur from the conditions
of use due to releases to air, water or land. The exposures to the general population via surface water,
drinking water, ambient air and sediment pathways falls under the jurisdiction of other environmental
statutes administered by EPA, i.e., CAA, SDWA, CWA, and RCRA. As explained in more detail in
section 1.4.2, EPA believes it is both reasonable and prudent to tailor TSCA risk evaluations when other
EPA offices have expertise and experience to address specific environmental media, rather than attempt
to evaluate and regulate potential exposures and risks from those media under TSCA. EPA believes that
coordinated action on exposure pathways and risks addressed by other EPA-administered statutes and
regulatory programs is consistent with statutory text and legislative history, particularly as they pertain
to TSCA's function as a "gap-filling" statute, and also furthers EPA aims to efficiently use Agency
resources, avoid duplicating efforts taken pursuant to other Agency programs, and meet the statutory
deadline for completing risk evaluations. EPA has therefore tailored the scope of the risk evaluation for
methylene chloride using authorities in TSCA sections 6(b) and 9(b)(1). EPA did not evaluate hazards
or exposures to the general population in this risk evaluation, and as such the unreasonable risk
determinations for relevant conditions of use do not account for exposures to the general population
(	2018c).
Unreasonable Risk of Injury to Health of Workers: EPA evaluated non-cancer effects from acute and
chronic inhalation and dermal occupational exposures and cancer from chronic inhalation and dermal
occupational exposures to determine if there was unreasonable risk to workers' health. The drivers for
EPA's determination of unreasonable risk of injury for workers are central nervous system effects
resulting from acute inhalation exposure, adverse effects to the liver due to chronic inhalation exposure,
and cancer from chronic inhalation.
EPA evaluated unreasonable risk to workers from dermal occupational exposure and determined
unreasonable risk to workers from dermal exposure from one condition of use: the industrial and
Page 37 of 753

-------
commercial use of methylene chloride in laundry and dishwashing, where EPA is not assuming use of
gloves in dry cleaning facilities.
EPA generally assumes compliance with OSHA requirements for protection of workers. In support of
this assumption, EPA used reasonably available information, including public comments, indicating that
some employers, particularly in the industrial setting, are providing appropriate engineering or
administrative controls or PPE to their employees consistent with OSHA requirements. While EPA does
not have similar information to support this assumption for each condition of use, EPA does not believe
that the Agency must presume, in the absence of such information, a lack of compliance with existing
regulatory programs and practices. Rather, EPA assumes there is compliance with worker protection
standards unless case-specific facts indicate otherwise, and therefore existing OSHA regulations for
worker protection and hazard communication will result in use of appropriate PPE in a manner that
achieves the stated APF or PF. EPA's decisions for unreasonable risk to workers are based on high-end
exposure estimates, in order to account for the uncertainties related to whether or not workers are using
PPE. EPA believes this is a reasonable and appropriate approach that reflects real-world scenarios,
accounts for reasonably available information related to worker protection practices, and addresses
uncertainties regarding availability and use of PPE.
For each condition of use of methylene chloride with an identified risk for workers, EPA assumes, as a
baseline, the use of a respirator with an APF of 25 or 50. Similarly, EPA assumes the use of gloves with
PF of 5 and 10 in commercial settings and gloves with PF of 5 and 20 in industrial settings. However,
EPA assumes that for some conditions of use, the use of appropriate respirators is not a standard
industry practice, based on best professional judgement given the burden associated with the use of
supplied-air respirators, including the expense of the equipment and the necessity of fit-testing and
training for proper use. Similarly, EPA does not assume that as a standard industry practice that workers
in dry cleaning facilities use gloves for spot cleaning.
The unreasonable risk determinations reflect the severity of the effects associated with the occupational
exposures to methylene chloride and incorporate consideration of the PPE that EPA assumes (respirator
of APF 25 or 50 and gloves with PF 5, 10, or 20). A full description of EPA's unreasonable risk
determination for each condition of use is in section 5.2.
Unreasonable Risk of Injury to Health of Occupational Non-Users (ONUs): EPA evaluated non-cancer
effects to ONUs from acute and chronic inhalation occupational exposures and cancer from chronic
inhalation occupational exposures to determine if there was unreasonable risk of injury to ONUs' health.
The unreasonable risk determinations reflect the severity of the effects associated with the occupational
exposures to methylene chloride and the assumed absence of PPE for ONUs, since ONUs do not directly
handle the chemical and are instead doing other tasks in the vicinity of methylene chloride use. Non-
cancer effects and cancer from dermal occupational exposures to ONUs were not evaluated because
ONUs are not dermally exposed to methylene chloride. For inhalation exposures, EPA, where possible,
estimated ONUs' exposures and described the risks separately from workers directly exposed. When the
difference between ONUs' exposures and workers' exposures cannot be quantified, EPA assumed that
ONU inhalation exposures are lower than inhalation exposures for workers directly handling the
chemical substance, and EPA considered the central tendency risk estimate when determining ONU risk.
A full description of EPA's unreasonable risk determination for each condition of use is in section 5.2.
Unreasonable Risk of Injury to Health of Consumers: EPA evaluated non-cancer effects to consumers
from acute inhalation and dermal exposures to determine if there was unreasonable risk to consumers'
health. A consumer condition of use sometimes was evaluated using multiple Consumer Exposure
Page 38 of 753

-------
Scenarios. In the Draft Risk Evaluation, EPA used the results from each Consumer Exposure Scenario to
draft separate preliminary unreasonable risk determinations, which resulted in multiple preliminary
unreasonable risk determinations for a single condition of use (e.g., consumer use in metal degreasers
had three unreasonable risk determinations). In this Final Risk Evaluation, EPA consolidated risk
estimates for multiple exposure scenarios in order to present clearer unreasonable risk determinations
and the unreasonable risk determinations adhere to the conditions of use as they were presented in the
Problem Formulation; as a result, in some cases a single determination may be informed by multiple risk
estimates from multiple Consumer Exposure Scenarios. Therefore, whereas the draft Risk Evaluation
presented 29 consumer risk determinations on 12 conditions of use, the Final Evaluation shows only the
12. Overall, the Draft Risk Evaluation had 71 unreasonable risk determinations, whereas the Final Risk
Evaluation determination has 53 unreasonable risk determinations. The exposure scenarios supporting
the unreasonable risk determinations for the conditions of use are listed in the detailed description of
each consumer use and listed in Table 5-2.
Unreasonable Risk of Injury to Health of Bystanders (from Consumer Uses): EPA evaluated non-cancer
effects to bystanders from acute inhalation exposures to determine if there was unreasonable risk of
injury to bystanders' health. EPA did not evaluate non-cancer effects from dermal exposures to
bystanders because bystanders are not dermally exposed to methylene chloride. A full description of
EPA's unreasonable risk determination for each condition of use is in section 5.2.
Summary of Unreasonable Risk Determinations:
In conducting risk evaluations, "EPA will determine whether the chemical substance presents an
unreasonable risk of injury to health or the environment under each condition of use within the scope of
the risk evaluation..40 CFR 702.47. Pursuant to TSCA section 6(i)(l), a determination of "no
unreasonable risk" shall be issued by order and considered to be final agency action. This subsection of
the final risk evaluation therefore constitutes the order required under TSCA section 6(i)(l), and the "no
unreasonable risk" determinations in this subsection are considered to be final agency action effective on
the date of issuance of this order.
EPA has determined that the following conditions of use of methylene chloride do not present an
unreasonable risk of injury to health or the environment. These determinations are considered final
agency action and are being issued by order pursuant to TSCA section 6(i)(l). The details of these
determinations are in section 5.2, and the TSCA section 6(i)(l) order is contained in Section 5.4.1 of this
final risk evaluation.
Conditions of I so llisit Do Not Present sin I nre;is<>ii;ihie Kisk
	Manufacturing (Domestic Manufacture)
	Processing: as a reactant
	Processing: recycling
	Distribution in commerce
	Industrial and commercial use as laboratory chemical
	Disposal
Page 39 of 753

-------
EPA has determined that the following conditions of use of methylene chloride present an unreasonable
risk of injury to health. EPA will initiate TSCA section 6(a) risk management actions on these
conditions of use as required under TSCA section 6(c)(1). Pursuant to TSCA section 6(i)(2), the
unreasonable risk determinations for these conditions of use are not considered final agency action. The
details of these determinations are in section 5.2.
.Msiniirsicliiring llisil Presents ;i 11 I nresisonsihle Risk
 Import
Processing 1 h:il Present sin I nresisonsihle Risk
	Processing: incorporation into a formulation, mixture, or reaction products
	Processing: repackaging
Imliislrisil sinri (ommercisil I ses 1 lint Present :in I nresisonsihle Kisk
Industrial and
commercial
use
as
solvent for batch vapor degreasing
Industrial and
commercial
use
as
solvent for in-line vapor degreasing
Industrial and
commercial
use
as
solvent for cold cleaning
Industrial and
commercial
use
as
solvent for aerosol spray degreaser/cleaner
Industrial and
commercial
use
in
adhesives, sealants and caulks
Industrial and
commercial
use
in
paints and coatings
Industrial and
commercial
use
in
paint and coating removers
Industrial and
commercial
use
in
adhesive and caulk removers
Industrial and
commercial
use
in
metal aerosol degreasers
Industrial and
commercial
use
in
metal non-aerosol degreasers
Industrial and
commercial
use
in
finishing products for fabric, textiles and leather
Industrial and
conditioners)
commercial
use
in
automotive care products (functional fluids for air
Industrial and
commercial
use
in
automotive care products (interior car care)
Industrial and
commercial
use
in
automotive care products (degreasers)
Industrial and
commercial
use
in
apparel and footwear care products
Industrial and
commercial
use
in
spot removers for apparel and textiles
Industrial and
commercial
use
in
liquid lubricants and greases
Page 40 of 753

-------
Indnslriiil ;iml (ommercinl I ses thill Present :i 11 I nre;isn:ihle Risk
Industrial and commercial use in spray lubricants and greases
Industrial and commercial use in aerosol degreasers and cleaners
Industrial and commercial use in non-aerosol degreasers and cleaners
Industrial and commercial use in cold pipe insulations
Industrial and commercial use as solvent that becomes part of a formulation or mixture
Industrial and commercial use as a processing aid
Industrial and commercial use as propellant and blowing agent
Industrial and commercial use for electrical equipment, appliance, and component
manufacturing
Industrial and commercial use for plastic and rubber products manufacturing
Industrial and commercial use in cellulose triacetate film production
Industrial and commercial use as anti-spatter welding aerosol
Industrial and commercial use for oil and gas drilling, extraction, and support activities
Industrial and commercial use in toys, playground and sporting equipment
Industrial and commercial use in lithographic printing plate cleaner
Industrial and commercial use in carbon remover, wood floor cleaner, and brush cleaner
Coi
inner I ses lluil Present ;i 11 I nrensonnhle Kisk
Consumer use as solvent in aerosol degreasers/cleaners
Consumer use in adhesives and sealants
Consumer use in brush cleaners for paints and coatings
Consumer use in adhesive and caulk removers
Consumer use in metal degreasers
Consumer use in automotive care products (functional fluids for air conditioners)
Consumer use in automotive care products (degreasers)
Consumer use in lubricants and greases
Consumer use in cold pipe insulation
Consumer use in arts, crafts, and hobby materials glue
Consumer use in an anti-spatter welding aerosol
Page 41 of 753

-------
C onsumer I scs llisil Prcscnl sin I nrcsisonsihlc Kisk
 Consumer use in carbon removers and other brush cleaners
1 INTRODUCTION
This document represents the final risk evaluation for methylene chloride under the Frank R. Lautenberg
Chemical Safety for the 21st Century Act. The Frank R. Lautenberg Chemical Safety for the 21st
Century Act amended the Toxic Substances Control Act (TSCA), the Nation's primary chemicals
management law, in June 2016.
The Environmental Protection Agency (EPA) published the Scope of the Risk Evaluation for
methylene chloride in June 2017 (U.S. EPA. 2017c). and the problem formulation in June 2018 (
EPA. 2018c). which represented the analytical phase of risk evaluation in which "the purpose for the
assessment is articulated, the problem is defined, and a plan for analyzing and characterizing risk is
determined," as described in Section 2.2 of the Framework for Human Health Risk Assessment to
Inform Decision Making. The problem formulation identified conditions of use and presented three
conceptual models and an analysis plan. Based on EPA's analysis of the conditions of use, physical-
chemical and fate properties, environmental releases, and exposure pathways, the problem formulation
preliminarily concluded that further analysis was necessary for exposure pathways to ecological
receptors exposed via surface water, workers, and consumers. EPA subsequently published a draft risk
evaluation for methylene chloride and has taken public and peer review comments. The conclusions,
findings, and determinations in this final risk evaluation are for the purpose of identifying whether the
chemical substance presents unreasonable risk or no unreasonable risk under the conditions of use, in
accordance with TSCA Section 6, and are not intended to represent any findings under TSCA Section
7.
As per EPA's final rule, Procedures for Chemical Risk Evaluation Under the Amended Toxic
Substances Control Act (82 FR 33726 (July 20, 2017)), this risk evaluation was subject to both public
comment and peer review, which are distinct but related processes. EPA provided 60 days for public
comment on any and all aspects of this risk evaluation, including the submission of any additional
information that might be relevant to the science underlying the risk evaluation and the outcome of the
systematic review associated with methylene chloride. This satisfies TSCA (15 U.S.C. 2605(b)(4)(H)),
which requires EPA to provide public notice and an opportunity for comment on a draft risk evaluation
prior to publishing a final risk evaluation.
Peer review was conducted in accordance with EPA's regulatory procedures for chemical risk
evaluations, including using the EPA Peer Review Handbook and other methods consistent with the
science standards laid out in Section 26 of TSCA {See 40 CFR 702.45). As explained in the Risk
Evaluation Rule (82 FR 33726 (July 20, 2017)), the purpose of peer review is for the independent
review of the science underlying the risk assessment. As such, peer review addressed aspects of the
underlying science as outlined in the charge to the peer review panel such as hazard assessment,
assessment of dose-response, exposure assessment, and risk characterization.
As EPA explained in the Risk Evaluation Rule (82 FR 33726 (July 20, 2017)), it is important for peer
reviewers to consider how the underlying risk evaluation analyses fit together to produce an integrated
risk characterization, which forms the basis of an unreasonable risk determination. EPA believed peer
reviewers were most effective in this role if they received the benefit of public comments on draft risk
Page 42 of 753

-------
evaluations prior to peer review. For this reason, and consistent with standard Agency practice, the
public comment period preceded peer review. The final risk evaluation changed in response to public
comments received on the draft risk evaluation and/or in response to peer review, which itself may be
informed by public comments. EPA responded to public and peer review comments received on the
draft risk evaluation and explained changes made in response to those comments in this final risk
evaluation and the associated response to comments document.
In this final risk evaluation, Section 1.1 presents the basic physical-chemical characteristics of
methylene chloride, as well as a background on regulatory history, conditions of use, and conceptual
models, with particular emphasis on any changes since the publication of the draft risk evaluation. This
section also includes a discussion of the systematic review process utilized in this final risk evaluation.
Section 2 provides a discussion and analysis of the exposures, both health and environmental, that can
be expected based on the conditions of use for methylene chloride. Section 3 discusses environmental
and health hazards of methylene chloride. Section 4 presents the risk characterization, where EPA
integrates and assesses reasonably available information on health and environmental hazards and
exposures, as required by TSCA (15 U.S.C. 2605(b)(4)(F)). This section also includes a discussion of
any uncertainties and how they impact the final risk evaluation. Section 5 presents EPA's determination
of whether the chemical presents an unreasonable risk under the conditions of use, as required under
TSCA (15 U.S.C. 2605(b)(4)).
EPA also solicited input on the first 10 chemicals as it developed use documents, scope documents, and
problem formulations. At each step, EPA has received information and comments specific to individual
chemicals and of a more general nature relating to various aspects of the risk evaluation process,
technical issues, and the regulatory and statutory requirements. EPA has considered comments and
information received at each step in the process and factored in the information and comments as the
Agency deemed appropriate and relevant including comments on the published problem formulation of
methylene chloride.
1.1 Physical and Chemical Properties
Physical-chemical properties influence the environmental behavior and the toxic properties of a
chemical, thereby informing the potential conditions of use, exposure pathways and routes and hazards
that EPA is evaluating. For scope development, EPA considered the measured or estimated physical-
chemical properties set forth in Table 1-1. EPA found no additional information during the process of
drafting the risk evalution, not did it hear of any information from the peer review or public commenters
that would change these values for the final risk evaluation.
Table 1-1. Physical and Chemical Properties of Methylene Chloride
Property
Measured Values
References
Data Quality
Rating
Molecular formula
CH2CI2


Molecular weight
84.93 g/mol


Physical form
Colorless liquid; sweet,
pleasant odor resembling
chloroform
U.S. Coast Gua 4)
High
Melting point
-95C
O'Neil C
High
Boiling point
39.7C
O'Neil C
High
Page 43 of 753

-------
Property
Measured \ sillies
References
l):il:i Qunlily
Killing
Density
1.33 g/cm3 at 20C
O'Neil C
High
Vapor pressure
435 mmHg at 25C
BoubMk 4)
High
Vapor density
2.93 (relative to air)
Holbrook (2003)
High
Water solubility
13 g/L at 25C
Horvath (1982)
High
Octanol/water partition
coefficient (log Kow)
1.25
Hansch et al. (1995)
High
Octanol/air partition
coefficient (log Koa)
2.27
\ v
High
Henry's Law constant
0.00291 atm-m3/mole
(equivalent to
concentr ati on/concentrati on
dimensionless 0.119)
Leigh ton an 81)
High

Flash point
Not readily available


Autoflammability
Not readily available


Viscosity
0.437 rnPa-s at 20C
Rossberg et al. (2011)
High
Refractive index
1.4244 at 20C
O'Neil C
High
Dielectric constant
9.02 at 20C
Laurence et 34)
High
1.2 Uses and Production Volume
Methylene chloride has a wide-range of uses, including in sealants, automotive products, and paint and
coating removers. EPA assessed paint removers containing methylene chloride in a previous risk
assessment but only previously finalized an unreasonable risk determination for the consumer paint and
coating remover condition of use (U.S. EPA. 2014). The use of paint and coating removers containing
methylene chloride in industrial or commercial sectors are included in this risk evaluation; the resultant
analysis is described in Appendix L. Methylene chloride is also used by federal agencies in a variety of
uses, including those deemed mission critical.
Methylene chloride has known applications as a process solvent in paint removers and the manufacture
of pharmaceuticals and film coatings. It is used as an agent in urethane foam blowing and in the
manufacture of hydrofluorocarbon (HFC) refrigerants, such as HFC-32. It can also be found in aerosol
propellants and in solvents for electronics manufacturing, metal cleaning and degreasing, and furniture
finishing. Additionally, it has been used for agricultural and food processing purposes such as an
extraction solvent for spice oleoresins, hops, and for the removal of caffeine from coffee, a degreening
agent for citrus fruits, and a postharvest fumigant for grains and strawberries (Processing Magazine.
JO I r. H1, -'000). However methylene chloride is no longer contained in any registered pesticide
products and was removed from the list of pesticide product inert ingredients (63 FR 34384, June 24,
1998) and tolerance exemptions for methylene chloride in foods were revoked (67 FR 16027, April 4,
2002) (see Appendix A for more information).
Page 44 of 753

-------
In 2005, the use percentages of methylene chloride by sector were as follows: paint stripping and
removal (30%), adhesives (22%), pharmaceuticals (11%), metal cleaning (8%), aerosols (8%), chemical
processing (8%), flexible polyurethane foam (5%), and miscellaneous (8%) ("ICIS. 2005).
As of 2016, the leading applications for methylene chloride are as a solvent in the production of
pharmaceuticals and polymers and paint removers, although recent regulations are expected to decrease
the chemical's use in the paint remover sector (40 CFR Part 751, Part B). An estimated 35 percent of
consumption is attributable to pharmaceuticals and chemical processing, with pharmaceutical production
accounting for roughly 30 percent of methylene chloride's use. Other applications include metal
cleaning, production of HFC-32, and as an ingredient in adhesives and paint removers. Foam blowing is
a minor use of methylene chloride (IH.S Markit. 2.016).
The Chemical Data Reporting (CDR) Rule under TSCA requires U.S. manufacturers (including
importers) to provide EPA with information on the chemicals they manufacture or import into the U.S.
For the 2016 CDR cycle, data collected per chemical include the company name, volume of each
chemical manufactured/imported, the number of workers at each site, and information on whether the
chemical is used in the Commercial, Industrial, and/or Consumer sector. However, only companies that
manufactured or imported 25,000 pounds or more of methylene chloride at each of their sites during the
2015 calendar year were required to report information under the CDR rule (	2016).
The 2016 CDR reporting data for methylene chloride are provided in Table 1-2. from EPA's CDR
database.
Table 1-2. Production Volume of Methylene Chloride in CDR Reporting Period (2012 to 2015)a
Reporting Yesir
2012
2013
2014
2015
Total Aggregate
Production Volume (lbs)
230,896,388
230,498,027
248,241,495
263,971,494
' The CDR data for the 2016 rcoortinu period is available via ChemVievv (httDs://iava.eDa.gov/chemview) (U.S. EPA.
20.1.6'). Because of an ongoing Confidential Business Information (CBI) substantiation process required by amended TSCA,
the CDR data available in the risk evaluation is more specific than currently in ChemView.
1.3 Regulatory and Assessment History
EPA conducted a search of existing domestic and international laws, regulations and assessments
pertaining to methylene chloride. EPA compiled this summary from available federal, state,
international and other government data sources, as cited in Appendix A.
Federal Laws and Regulations
Methylene chloride is subject to other federal statutes and regulations that are implemented by other
offices within EPA and/or other federal agencies/departments. A summary of federal laws, regulations
and implementing authorities is provided in Appendix A.l.
State Laws and Regulations
Methylene chloride is subject to state statutes and regulations implemented by state agencies or
departments. A summary of state laws, regulations and implementing authorities is provided in
Appendix A.2.
Page 45 of 753

-------
Laws and Regulations in Other Countries and International Treaties or Agreements
Methylene chloride is subject to statutes and regulations in countries other than the U.S. and/or
international treaties and/or agreements. A summary of these laws, regulations, treaties and/or
agreements is provided in Appendix A.3.
Assessment History
EPA identified assessments conducted by other EPA Programs and other organizations (see Table 1-3).
Depending on the source, these assessments may include information on conditions of use, hazards,
exposures and potentially exposed or susceptible subpopulations (PESS). EPA found no additional
assessments beyond those listed in the Problem Formulation document (see Table 1-1 in Methylene
Chloride Problem Formulation document).
Table 1-3. Assessment History of Methylene Chloride
Authoring Organization
Assessment
EPA Assessments
U.S. EPA, Office of Pollution Prevention and
Toxics (OPPT)
TSCA Work Plan Chemical Risk Assessment
Methylene Chloride: Paint Strippi : CASRN:
75-0
U.S. EPA, Integrated Risk Information System
(IRIS)
lexicological Review of Dichloromethane
(Methylene Chloride) (CAS No. 75-09-2) U.S.
U.S. EPA, Office of Water (OW)
Ambient Water Oualitv Criteria for the Protection
of Human Heal'
Other U.S.-Based Organizations
Agency for Toxic Substances and Disease Registry
(AT SDR)
Toxicological Profile for Methylene Chloride
\ ! ,.000) and ATSDk _VM) addendum
National Advisory Committee for Acute Exposure
Guideline Levels for Hazardous Substances
(NAC/AEGL Committee)
Interim Acute Exposure Guideline Level
for Methylene Chloride Nac/Aegl (2008b)

U.S. National Academies, National Research
Council (NRC)
Spacecraft Maximum Allowable Concentrations
(SMAC) for Selected Airborne Contaminants:
Methylene chloride (Volume 2) Nrc (1996)
National Toxicology Program (NTP), National
Institutes of Health (NIH)
Report on Carcinogens. Tweli ion.
Dichloromethane NIH (2016)
Occupational Safety and Health Administration
(OSHA)
Occupational Exposure to Methylene Chloride
OSH
California Environmental Protection Agency,
Office of Environmental Health Hazard
Assessment (OEHHA)
Acute Reference Exposure Level (RED and
Toxicity Summary for Methylene Chloride Oehha
(2008a)
Public Health Goal for Methylene Chloride in
Drinking Water Oehha (2000)
Page 46 of 753

-------
Authoring Organization
Assessment
International
Organisation for Economic Co-operation and
Development (OECD), Cooperative Chemicals
Assessment Program (CoCAP)
Dichloromethane: SIDS Initial Assessme lie
OECD (:
International Agency for Research on Cancer
(IARC)
IARC Monographs on. the Evaluation of
Carcinogenic Risks to Humans Volui

World Health Organization (WHO)
Air Oual delines for Europe WHO (2000)
WHO International Programme on Chemical
Safety (IPCS)
Environmental Health Criteria 164 Methylene
Chloride WHO (1996b)
Government of Canada, Environment Canada,
Health Canada
Dichloromethane. Priority substances list
assessment report. Health Canada (1993)
National Industrial Chemicals Notification and
Assessment Scheme (NICNAS), Australian
Government
Human Health Tier essment for Methane.
dicM.no t \ umbei " << ... \ i' \ \S ,2
-------
MFG/IMPORT	PROCESSING	INDUSTRIAL, COMMERCIAL, CONSUMER USESa	RELEASES and WASTE DISPOSAL
Solvents for Cleaning or Degreasing
(Volume CBI)
Adhesives and Sealants
(Volume CBI)
e.g., glues and caulks
Paints and Coatings
(> 839,000 lbs)
Including Paint and coating removers for
furniture stripping and adhesive removers
Metal Products
(Volume CBI)
Fabric, Textile, and Leather Products
(Volume CBI)
Automotive Care Products
(11,000 lbs)
Apparel and Footwear Care Products
(Volume CBI)
See Figure 1-4 for Environmental
Releases and Wastes
Laundry and Dishwashing Products
(Volume CBI)
] Manufacturing (includes import)
Lubricants and Greases
(187,000 lbs)
] Processing
Other Uses including
Building/Construction Materials Not Covered
Elsewhere; Solvents (which become part of
product formation or mixture); Processing Aids
Not Otherwise Listed; Propellantsand Blowing
Agents; Arts, Crafts and Hobby Materials;
Functional fluids (closed systems); Laboratory
Chemicals
~ Uses. At the level of detail in the life cycle
diagram EPA is not distinguishing between
industrial/commercial/consumer uses. The
differences between these uses will be
further investigated and defined during risk
evaluation.
Recycling
(Volume CBI)
Repackaging
(> 227,000 lbs)
Manufacturing
(includes import)
(264 million lbs)
Processing as Reactant
(Volume CBI)
e.g., intermediate for
refrigerant manufacture
Incorporated into
Formulation, Mixture
or Reaction Product
(> 557,000 lbs)
e.g., Polyurethane Foam
Blowing
Disposal
Figure 1-1. Methylene Chloride Life Cycle Diagram
The life cycle diagram depicts the conditions of use that are within the scope of the risk evaluation during various life cycle stages including manufacturing, processing,
use (industrial, commercial, consumer), distribution and disposal. The production volumes shown are for reporting year 2015 from the 2016 CDR reporting period (U.S.
EPA. 2016). Activities related to distribution (e.g., loading and unloading) are evaluated throughout the methylene chloride life cycle, rather than using a single
distribution scenario.
a See Table 1-4 for additional uses not mentioned specifically in this diagram.
Page 48 of 753

-------
Table 1-4. Categories and Subcategories of Conditions of Use Included in the Scope of the
Risk Evaluation
1 ,ilc ( vcle
Stage
Cal ego rv 11
Subcategory h
References
Manufacturing
Domestic
manufacturing
Manufacturing
I S t v- \ < >0k0

Import
Import
1 \ t 201* )
Processing
Processing as a
reactant
Intermediate in industrial gas
manufacturing (e.g.,
manufacture of fluorinated
gases used as refrigerants)
U.S. EPA. (2016); U.S.
EPA (2014) Market
profile EPA-HQ-OPPT-
2016-0742 Public
Comments EPA-HO-
,
EP A-HO-OPPT-2016-
0' -i-ui!,i i N>4-H\}-
OPPT-2016-0742-0019
Intermediate for pesticide,
fertilizer, and other agricultural
chemical manufacturing
1 \ t 201* )
Petrochemical manufacturing*
1 i\ 1201*)
Intermediate for other
chemicals
Public Comment EPA-
HO-OPPT-2016-0742-
0008
Incorporated into
formulation,
mixture, or
reaction product
Solvents (for cleaning or
degreasing), including
manufacturing of:
	All other basic organic
chemical
	Soap, cleaning
compound and toilet
preparation
' r \ v201 )

Solvents (which become part of
product formulation or
mixture), including
manufacturing of:
	All other chemical
product and preparation
	Paints and coatings
5 r > i" \ ^20! )

Page 49 of 753

-------
Life Cycle
Slsige
Category 11
Subcategory h
References


Propel liinls and Mowing agents
for all other chemical product
and preparation manufacturing;

Propellants and blowing agents
for plastics product
manufacturing
Use document EPA-HO-
OPPT-21 3.
Market profile EPA-HQ-
Paint additives and coating
additives not described by
other codes for CBI industrial
sector*
! t { \ <-OkO
Laboratory chemicals for all
other chemical product and
preparation manufacturing
U.S. EPA. (20161 EPA-
HO-OPPT-2016-0742-
O'jO . NVUUMWl"-
,v.| u ! 
Laboratory chemicals for other
industrial sectors*
1 \ t 201* )
Processing aid, not otherwise
listed for petrochemical
manufacturing
U.S. EPA. C

Adhesive and sealant
chemicals in adhesive
manufacturing
Use document
3;
oil and gas drilling, extraction,
and support activities*
Use document
OPPT-2016-0742-0003;
Repackaging
Solvents (which become part of
product formulation or
mixture) for all other chemical
product and preparation
manufacturing
Use document
3;

all other chemical product and
preparation manufacturing*
Use document
3;

Recycling
Recycling
U.S. EPA (201 *c)
Page 50 of 753

-------
Life ( vole
Slsige
Category 11
Subcategory h
References
Distribution in
commerce
Distribution
Distii billion
I sc document
OPPT-21 3
Industrial,
commercial and
consumer uses
Solvents (for
cleaning or
degreasing)c
Batch vapor degreaser (e.g.,
open-top, closed-loop)
Use document EPA-HO-
OPPT-21 3:
, Public
comment EPA-HO-
OPPT-21


In-line vapor degreaser (e.g.,
conveyorized, web cleaner)
Use document EPA-HO-
OPPT-21 3:
, Public
comment


Cold cleaner
Use document EPA-HO-
OPPT-21 3:
\ r ir \ v>i , n


Aerosol spray
degreaser/cleaner
3-OPPT-
3; Market
profile EPA-HO-OPPT-

Adhesives and
sealants
Single component glues and
adhesives and sealants and
caulks
Use document EPA-HO-
OPPT-21 3;
, Public
comments EPA-HO-
OPPT-2016-0742-0005.
EP A-HO-OPPT-2016-
0/ li 00H, I i1 \ il(h
OPPT-2016-0742-0014.
EP A-HO-OPPT-2016-
0742.-0017. EPA-HO-
OPPT-2016-0742-0021.
EP A-HO-OPPT-2016-
0742-00.33
Page 51 of 753

-------
Life Cycle
Slsige
Category 11
Subcategory h
References

Piiiills and
coatings
including
commercial paint
and coating
removers 6
Paints and coalings use and
commercial paints and coating
removers
2014b); Market profile
EP A-HO-OPPT-2016-
0742 Public Comments
EP A-HO-OPPT-2016-
0742-OOOx !l>\i(0-
9,
PPI-2016-
0 _ OiM S, 1 ! I t. j
, 11 * 1!  [ - mi" j <	 ,
[rvi-io-owi -20 ii 6-
" ! ' 1, M'A 11"^
<.>nvl-2'U6-0"-l2-'i025
Adhesive/caulk removers
Use document EPA-HO-
OPPT-21 3.
Market profile EPA-HO-
OPPT-2016-0742
Metal products
not covered
elsewhere
Degreasers - aerosol and non-
aerosol degreasers and cleaners
(e.g., coil cleaners)
Market profile EPA-HO-
PPA (20 |n)
Fabric, textile
and leather
products not
covered
elsewhere
Textile finishing and
impregnating/surface treatment
products (e.g., water repellant)
Market profile EPA-HQ-
OPPT-2016-0742

Automotive care
products
Function fluids for air
conditioners: refrigerant,
treatment, leak sealer
Use document EPA-HO-
Oppt-21 3;
Market orofile EPA-HO-
,
EPA. (2.016)
Interior car care - spot remover
Use document EPA-HO-
OPPT-21 3
Degreasers: gasket remover,
transmission cleaners,
carburetor cleaner, brake
quieter/cleaner
Use document EPA-HO-
OPPT-21 3.
Market orofile EPA-HO-
,
Page 52 of 753

-------
Life Cycle
Slsige
Category 11
Subcategory h
References

Apparel and
footwear care
products
Posl-mai'kel waxes and
polishes applied to footwear
(e.g., shoe polish)
Market profile

Laundry and
dishwashing
products
Spot remover for apparel and
textiles
Use document EPA-HO-
OPPT-21 3

Lubricants and
greases
Liquid and spray lubricants and
greases
U.S. EPA. (2016); EPA-
HO-OPPT-2016-0742-
0003; Market profile
EP A-HO-OPPT-2016-
0742; Public Comment
)-OPPT-2016-
Degreasers - aerosol and non-
aerosol degreasers and cleaners
U.S. EPA (20161 i b X
HO-OPPT-2.016-0742-
0003; Market profile
EP A-HO-OPPT-2016-
0742; Public Comments
EP A-HO-OPPT-2016-
0742-00" \ I-1- \lj
HI-1 '11" 1 o .. 4 '  | -I
Building/
construction
materials not
covered
elsewhere
Cold pipe insulation
Use document EPA-HO-
OPPT-21

Solvents (which
become part of
product
formulation or
mixture)
All other chemical product and
preparation manufacturing
I S i v- \ ,-Oiu)
Processing aid
not otherwise
listed
In multiple manufacturing
sectors'1
Use document EPA-HO-
OPPT-21 3;
Market profile EPA-HO-
;

Propellants and
blowing agents
Flexible polyurethane foam
manufacturing
Market profile EPA-HO-

Page 53 of 753

-------
Life Cycle
Slsige
Category 11
Subcategory h
References

Ails, ciafls and
hobby materials
Craflinu uluc and
cement/concrete
I sc document
OPPT-21 3
Other Uses
Laboratory chemicals - all
other chemical product and
preparation manufacturing
Use document EPA-HO-
OPPT-21 3:
Market profile EPA-HQ-
	 11 " " , Public
Comment: EPA-HQ-
OPPT-21 5
Electrical equipment,
appliance, and component
manufacturing
U.S. EPA. (20161 Public
Comment EPA-HO-
Plastic and rubber products

Anti-adhesive agent - anti-
spatter welding aerosol
Use document EPA-HO-
OPPT-21 3;
Market profile EPA-HO-
* rn  ! , Public
Comment EPA-HQ-
5
Oil and gas drilling, extraction,
and support activities
Use document EPA-HO-
OPPT-21 3;
Toys, playground, and sporting
equipment - including novelty
articles (toys, gifts, etc.)
Use document EPA-HO-
OPPT-2*l k L i
EP A-HO-OPPT-2016-
0742-0069:
Carbon remover, lithographic
printing cleaner, brush cleaner,
use in taxidermy, and wood
floor cleaner
Use document EPA-HO-
OPPT-2 M , k oou .
Market profile EPA-HQ-
OPPT-2016-0742; U.S.
EP A. (201 ti)
Disposal
Disposal
Industrial pre-treatment
U.S. EPA. C
Industrial wastewater treatment
Publicly owned treatment
works (POTW)
Underground injection
Page 54 of 753

-------
iIV Cycle
Slsigc
(si lego rv 11
Suhosilegorv
Uelerences
Municipal landfill
Hazardous landfill
Other land disposal
Municipal waste incinerator
Hazardous waste incinerator
Off-site waste transfer
Note that methylene chloride is used by federal agencies in a variety of uses, including some deemed mission
critical.
a These categories of conditions of use appear in the initial life cycle diagram, reflect CDR codes and broadly
represent conditions of use for methylene chloride in industrial and/or commercial settings.
b These subcategories reflect more specific uses of methylene chloride.
0 Reported for the following sectors in the 2016 CDR for manufacturing of: plastic materials and resins, plastics
products, miscellaneous, all other chemical product and preparation (U.S. EPA. 20.1.6').
d Reported for the following sectors in the 2016 CDR for manufacturing of: petrochemicals, plastic materials and
resins, plastics products, miscellaneous and all other chemical products * (U.S. EPA. 2016) also including as a
chemical processor for polycarbonate resins and cellulose triacetate (photographic film).
e Consumer paint and coating remover uses are already addressed through rulemaking (see 40 CFR Part 751,
Subpart B) and are outside the scope of this risk evaluation.
* Conditions of use with CBI or unknown function were evaluated and considered for the methylene chloride risk
evaluation; however, the non-CBI elements of the category, subcategory, function and industrial sector were used
in the analysis as these data were higher quality. This applies to: CBI function for petrochemical manufacturing,
paint additives and coating additives not described by other codes for CBI industrial sector, laboratory chemicals
for CBI industrial sectors, manufacturing of CBI and oil and gas drilling, extraction, and support activities.
** Although EPA has identified both industrial and commercial uses here for purposes of distinguishing scenarios
in this document, the Agency interprets the authority over "any manner or method of commercial use" under
TSCA section 6(a)(5) to reach both.
Page 55 of 753

-------
1.4.2 Exposure Pathways and Risks Addressed by Other EPA-Administered
Statutes5
In its TSCA section 6(b) risk evaluations, EPA is coordinating action on certain exposure
pathways and risks falling under the jurisdiction of other EPA-administered statutes or regulatory
programs. More specifically, EPA is exercising its TSCA authorities to tailor the scope of its
risk evaluations, rather than focusing on environmental exposure pathways addressed under other
EPA-administered statutes or regulatory programs or risks that could be eliminated or reduced to
a sufficient extent by actions taken under other EPA-administered laws. EPA considers this
approach to be a reasonable exercise of the Agency's TSCA authorities, which include:
	TSCA section 6(b)(4)(D): "The Administrator shall, not later than 6 months after the
initiation of a risk evaluation, publish the scope of the risk evaluation to be conducted,
including the hazards, exposures, conditions of use, and the potentially exposed or
susceptible subpopulations the Administrator expects to consider.
	TSCA section 9(b)(1): "The Administrator shall coordinate actions taken under this
chapter with actions taken under other Federal laws administered in whole or in part by
the Administrator. If the Administrator determines that a risk to health or the environment
associated with a chemical substance or mixture could be eliminated or reduced to a
sufficient extent by actions taken under the authorities contained in such other Federal
laws, the Administrator shall use such authorities to protect against such risk unless the
Administrator determines, in the Administrator's discretion, that it is in the public interest
to protect against such risk by actions taken under this chapter."
	TSCA section 9(e): "...[I]f the Administrator obtains information related to exposures or
releases of a chemical substance or mixture that may be prevented or reduced under
another Federal law, including a law not administered by the Administrator, the
Administrator shall make such information available to the relevant Federal agency or
office of the Environmental Protection Agency."
	TSCA section 2(c): "It is the intent of Congress that the Administrator shall carry out
this chapter in a reasonable and prudent manner, and that the Administrator shall consider
the environmental, economic, and social impact of any action the Administrator takes or
proposes as provided under this chapter."
	TSCA section 18(d)(1): "Nothing in this chapter, nor any amendment made by the Frank
R. Lautenberg Chemical Safety for the 21st Century Act, nor any rule, standard of
performance, risk evaluation, or scientific assessment implemented pursuant to this
chapter, shall affect the right of a State or a political subdivision of a State to adopt or
enforce any rule, standard of performance, risk evaluation, scientific assessment, or any
other protection for public health or the environment that (i) is adopted or authorized
under the authority of any other Federal law or adopted to satisfy or obtain authorization
or approval under any other Federal law..."
TSCA authorities supporting tailored risk evaluations and intra-agencv referrals
5 The statutory interpretations and approach described in this subsection will apply to all TSCA risk evaluations and
are not limited in application to this final risk evaluation for methylene chloride.
Page 56 of 753

-------
TSCA section 6(b)(4)(D)
TSCA section 6(b)(4)(D) requires EPA, in developing the scope of a risk evaluation, to identify
the hazards, exposures, conditions of use, and potentially exposed or susceptible subpopulations
the Agency "expects to consider" in a risk evaluation. This language suggests that EPA is not
required to consider all conditions of use, hazards, or exposure pathways in risk evaluations. As
EPA explained in the "Procedures for Chemical Risk Evaluation Under the Amended Toxic
Substances Control Act" ("Risk Evaluation Rule"), "EPA may, on a case-by-case basis, exclude
certain activities that EPA has determined to be conditions of use in order to focus its analytical
efforts on those exposures that are likely to present the greatest concern, and consequently merit
an unreasonable risk determination." 82 FR 33726, 33729 (July 20, 2017).
In the problem formulation documents for many of the first 10 chemicals undergoing risk
evaluation, EPA applied the same authority and rationale to certain exposure pathways,
explaining that "EPA is planning to exercise its discretion under TSCA 6(b)(4)(D) to focus its
analytical efforts on exposures that are likely to present the greatest concern and consequently
merit a risk evaluation under TSCA, by excluding, on a case-by-case basis, certain exposure
pathways that fall under the jurisdiction of other EPA-administered statutes." The approach
discussed in the Risk Evaluation Rule and applied in the problem formulation documents is
informed by the legislative history of the amended TSCA, which supports the Agency's exercise
of discretion to focus the risk evaluation on areas that raise the greatest potential for risk. See
June 7, 2016 Cong. Rec., S3519-S3520. Consistent with the approach articulated in the problem
formulation documents, and as described in more detail below, EPA is exercising its authority
under TSCA to tailor the scope of exposures evaluated in TSCA risk evaluations, rather than
focusing on environmental exposure pathways addressed under other EPA-administered, media-
specific statutes and regulatory programs.
TSCA section 9(b)(1)
In addition to TSCA section 6(b)(4)(D), the Agency also has discretionary authority under the
first sentence of TSCA section 9(b)(1) to "coordinate actions taken under [TSCA] with actions
taken under other Federal laws administered in whole or in part by the Administrator." This
broad, freestanding authority provides for intra-agency coordination and cooperation on a range
of "actions." In EPA's view, the phrase "actions taken under [TSCA]" in the first sentence of
section 9(b)(1) is reasonably read to encompass more than just risk management actions, and to
include actions taken during risk evaluation as well. More specifically, the authority to
coordinate intra-agency actions exists regardless of whether the Administrator has first made a
definitive finding of risk, formally determined that such risk could be eliminated or reduced to a
sufficient extent by actions taken under authorities in other EPA-administered Federal laws,
and/or made any associated finding as to whether it is in the public interest to protect against
such risk by actions taken under TSCA. TSCA section 9(b)(1) therefore provides EPA authority
to coordinate actions with other EPA offices without ever making a risk finding, or following an
identification of risk. This includes coordination on tailoring the scope of TSCA risk evaluations
to focus on areas of greatest concern rather than exposure pathways addressed by other EPA-
Page 57 of 753

-------
administered statutes and regulatory programs, which does not involve a risk determination or
public interest finding under TSCA section 9(b)(2).
In a narrower application of the broad authority provided by the first sentence of TSCA section
9(b)(1), the remaining provisions of section 9(b)(1) provide EPA authority to identify risks and
refer certain of those risks for action by other EPA offices. Under the second sentence of section
9(b)(1), "[i]f the Administrator determines that a risk to health or the environment associated
with a chemical substance or mixture could be eliminated or reduced to a sufficient extent by
actions taken under the authorities contained in such other Federal laws, the Administrator shall
use such authorities to protect against such risk unless the Administrator determines, in the
Administrator's discretion, that it is in the public interest to protect against such risk by actions
taken under [TSCA]." Coordination of intra-agency action on risks under TSCA section 9(b)(1)
therefore entails both an identification of risk, and a referral of any risk that could be eliminated
or reduced to a sufficient extent under other EPA-administered laws to the EPA office(s)
responsible for implementing those laws (absent a finding that it is in the public interest to
protect against the risk by actions taken under TSCA).
Risk may be identified by OPPT or another EPA office, and the form of the identification may
vary. For instance, OPPT may find that one or more conditions of use for a chemical substance
present(s) a risk to human or ecological receptors through specific exposure routes and/or
pathways. This could involve a quantitative or qualitative assessment of risk based on
reasonably available information (which might include, e.g., findings or statements by other EPA
offices or other federal agencies). Alternatively, risk could be identified by another EPA office.
For example, another EPA office administering non-TSCA authorities may have sufficient
monitoring or modeling data to indicate that a particular condition of use presents risk to certain
human or ecological receptors, based on expected hazards and exposures. This risk finding
could be informed by information made available to the relevant office under TSCA section 9(e),
which supports cooperative actions through coordinated information-sharing.
Following an identification of risk, EPA would determine if that risk could be eliminated or
reduced to a sufficient extent by actions taken under authorities in other EPA-administered laws.
If so, TSCA requires EPA to "use such authorities to protect against such risk," unless EPA
determines that it is in the public interest to protect against that risk by actions taken under
TSCA. In some instances, EPA may find that a risk could be sufficiently reduced or eliminated
by future action taken under non-TSCA authority. This might include, e.g., action taken under
the authority of the Safe Drinking Water Act to address risk to the general population from a
chemical substance in drinking water, particularly if the Office of Water has taken preliminary
steps such as listing the subject chemical substance on the Contaminant Candidate List. This sort
of risk finding and referral could occur during the risk evaluation process, thereby enabling EPA
to use more a relevant and appropriate authority administered by another EPA office to protect
against hazards or exposures to affected receptors.
Legislative history on TSCA section 9(b)(1) supports both broad coordination on current intra-
agency actions, and narrower coordination when risk is identified and referred to another EPA
office for action. A Conference Report from the time of TSCA's passage explained that section
9 is intended "to assure that overlapping or duplicative regulation is avoided while attempting to
Page 58 of 753

-------
provide for the greatest possible measure of protection to health and the environment." S. Rep.
No. 94-1302 at 84. See also H. Rep. No. 114-176 at 28 (stating that the 2016 TSCA
amendments "reinforce TSCA's original purpose of filling gaps in Federal law," and citing new
language in section 9(b)(2) intended "to focus the Administrator's exercise of discretion
regarding which statute to apply and to encourage decisions that avoid confusion, complication,
and duplication"). Exercising TSCA section 9(b)(1) authority to coordinate on tailoring TSCA
risk evaluations is consistent with this expression of Congressional intent.
Legislative history also supports a reading of section 9(b)(1) under which EPA coordinates intra-
agency action, including information-sharing under TSCA section 9(e), and the appropriately-
positioned EPA office is responsible for the identification of risk and actions to protect against
such risks. See, e.g., Senate Report 114-67, 2016 Cong. Rec. S3522 (under TSCA section 9, "if
the Administrator finds that disposal of a chemical substance may pose risks that could be
prevented or reduced under the Solid Waste Disposal Act, the Administrator should ensure that
the relevant office of the EPA receives that information"); H. Rep. No. 114-176 at 28, 2016
Cong. Rec. S3522 (under section 9, "if the Administrator determines that a risk to health or the
environment associated with disposal of a chemical substance could be eliminated or reduced to
a sufficient extent under the Solid Waste Disposal Act, the Administrator should use those
authorities to protect against the risk"). Legislative history on section 9(b)(1) therefore supports
coordination with and referral of action to other EPA offices, especially when statutes and
associated regulatory programs administered by those offices could address exposure pathways
or risks associated with conditions of use, hazards, and/or exposure pathways that may otherwise
be within the scope of TSCA risk evaluations.
TSCA sections 2(c) & 18(d)(1)
Finally, TSCA sections 2(c) and 18(d) support coordinated action on exposure pathways and
risks addressed by other EPA-administered statutes and regulatory programs. Section 2(c)
directs EPA to carry out TSCA in a "reasonable and prudent manner" and to consider "the
environmental, economic, and social impact" of its actions under TSCA. Legislative history
from around the time of TSCA's passage indicates that Congress intended EPA to consider the
context and take into account the impacts of each action under TSCA. S. Rep. No. 94-698 at 14
("the intent of Congress as stated in this subsection should guide each action the Administrator
takes under other sections of the bill").
Section 18(d)(1) specifies that state actions adopted or authorized under any Federal law are not
preempted by an order of no unreasonable risk issued pursuant to TSCA section 6(i)(l) or a rule
to address unreasonable risk issued under TSCA section 6(a). Thus, even if a risk evaluation
were to address exposures or risks that are otherwise addressed by other federal laws and, for
example, implemented by states, the state laws implementing those federal requirements would
not be preempted. In such a case, both the other federal and state laws, as well as any TSCA
section 6(i)(l) order or TSCA section 6(a) rule, would apply to the same issue area. See also
TSCA section 18(d)(l)(A)(iii). In legislative history on amended TSCA pertaining to section
18(d), Congress opined that "[t]his approach is appropriate for the considerable body of law
regulating chemical releases to the environment, such as air and water quality, where the states
Page 59 of 753

-------
have traditionally had a significant regulatory role and often have a uniquely local concern."
Sen. Rep. 114-67 at 26.
EPA's careful consideration of whether other EPA-administered authorities are available and
more appropriate for addressing certain exposures and risks is consistent with Congress' intent to
maintain existing federal requirements and the state actions adopted to locally and more
specifically implement those federal requirements, and to carry out TSCA in a reasonable and
prudent manner. EPA believes it is both reasonable and prudent to tailor TSCA risk evaluations
in a manner reflective of expertise and experience exercised by other EPA and State offices to
address specific environmental media, rather than attempt to evaluate and regulate potential
exposures and risks from those media under TSCA. This approach furthers Congressional
direction and EPA aims to efficiently use Agency resources, avoid duplicating efforts taken
pursuant to other Agency and State programs, and meet the statutory deadline for completing
risk evaluations.
EPA-administered statutes and regulatory programs that address specific exposure pathways
and/or risks
During the course of the risk evaluation process for methylene chloride, OPPT worked closely
with the offices within EPA that administer and implement regulatory programs under the Clean
Air Act (CAA), the Safe Drinking Water Act (SDWA), the Clean Water Act (CWA) and the
Resource Conservation and Recovery Act (RCRA). Through intra-agency coordination, EPA
determined that specific exposure pathways are well-regulated by the EPA statutes and
regulations described in the following paragraphs.
The CAA contains a list of hazardous air pollutants (HAP) and provides EPA with the authority
to add to that list pollutants that present, or may present, a threat of adverse human health effects
or adverse environmental effects. For stationary source categories emitting HAP, the CAA
requires issuance of technology-based standards and, if necessary, additions or revisions to
address developments in practices, processes, and control technologies, and to ensure the
standards adequately protect public health and the environment. The CAA thereby provides EPA
with comprehensive authority to regulate emissions to ambient air of any hazardous air pollutant.
Methylene Chloride is a HAP. See 42 U.S.C. 7412. EPA has issued a number of technology-
based standards for source categories that emit methylene chloride to ambient air and, as
appropriate, has reviewed, or is in the process of reviewing remaining risks. See 40 CFR part 63;
Appendix A. Because stationary source releases of methylene chloride to ambient air are
addressed under the CAA, EPA is not evaluating emissions to ambient air from commercial and
industrial stationary sources or associated inhalation exposure of the general population or
terrestrial species in this TSCA risk evaluation.
EPA has regular analytical processes to identify and evaluate drinking water contaminants of
potential regulatory concern for public water systems under the Safe Drinking Water Act
(SDWA). Under SDWA, EPA must also review and revise "as appropriate" existing drinking
water regulations every 6 years.
Page 60 of 753

-------
EPA has promulgated National Primary Drinking Water Regulations (NPDWRs) for methylene
chloride under SDWA. See 40 CFR part 151; Appendix A. EPA has set an enforceable
Maximum Contaminant Level (MCL) as close as feasible to a health based, non-enforceable
Maximum Contaminant Level Goal (MCLG). Feasibility refers to both the ability to treat water
to meet the MCL and the ability to monitor water quality at the MCL, SDWA Section
1412(b)(4)(D), and public water systems are required to monitor for the regulated chemical
based on a standardized monitoring schedule to ensure compliance with the maximum
contaminant level (MCL).
Hence, because the drinking water exposure pathway for methylene chloride is currently
addressed in the SDWA regulatory analytical process for public water systems, EPA is not
evaluating exposures to the general population from the drinking water exposure pathway in the
risk evaluation for methylene chloride under TSCA.
EPA develops recommended water quality criteria under section 304(a) of the CWA for
pollutants in surface water that are protective of aquatic life or human health designated uses.
EPA develops and publishes water quality criteria based on priorities of states and others that
reflect the latest scientific knowledge. A subset of these chemicals are identified as "priority
pollutants" (103 human health and 27 aquatic life). The CWA requires states adopt numeric
criteria for priority pollutants for which EPA has published recommended criteria under section
304(a), the discharge or presence of which in the affected waters could reasonably be expected to
interfere with designated uses adopted by the state. When states adopt criteria that EPA approves
as part of state's regulatory water quality standards, exposure is considered when state permit
writers determine if permit limits are needed and at what level for a specific discharger of a
pollutant to ensure protection of the designated uses of the receiving water. Once states adopt
criteria as water quality standards, the CWA requires that National Pollutant Discharge
Elimination System (NPDES) discharge permits include effluent limits as stringent as necessary
to meet standards. CWA section 301(b)(1)(C). This is the process used under the CWA to
address risk to human health and aquatic life from exposure to a pollutant in ambient waters.
EPA has identified methylene chloride as a priority pollutant and has developed recommended
water quality criteria for protection of human health for methylene chloride which are available
for adoption into state water quality standards for the protection of human health and are
available for use by NPDES permitting authorities in deriving effluent limits to meet state
criteria.6 See, e.g., 40 CFR part 423, Appendix A; 40 CFR 131.11(b)(1); 40 CFR 122.44(d)(vi).
As such, EPA is not evaluating exposures to the general population from the surface water
exposure pathway in the risk evaluation under TSCA.
Methylene chloride is included on the list of hazardous wastes pursuant to RCRA section 3001
(40 CFR  261.33) as a listed waste on the F001, F002, K009, K010, K156, K157, K158, and
U080 lists. The general standard in RCRA section 3004(a) for the technical criteria that govern
the management (treatment, storage, and disposal) of hazardous waste are those "necessary to
protect human health and the environment," RCRA 3004(a). The regulatory criteria for
identifying "characteristic" hazardous wastes and for "listing" a waste as hazardous also relate
solely to the potential risks to human health or the environment. 40 C.F.R.  261.11, 261.21-
6 See https://www.regulations.gov/document?D=EPA-HQ-OW-2014-0135-0200.
Page 61 of 753

-------
261.24. RCRA statutory criteria for identifying hazardous wastes require EPA to "tak[e] into
account toxicity, persistence, and degradability in nature, potential for accumulation in tissue,
and other related factors such as flammability, corrosiveness, and other hazardous
characteristics." Subtitle C controls cover not only hazardous wastes that are landfilled, but also
hazardous wastes that are incinerated (subject to joint control under RCRA Subtitle C and the
CAA hazardous waste combustion MACT) or injected into UIC Class I hazardous waste wells
(subject to joint control under Subtitle C and SDWA).
EPA is not evaluating emissions to ambient air from municipal and industrial waste incineration
and energy recovery units or associated exposures to the general population or terrestrial species
in the risk evaluation, as these emissions are regulated under section 129 of the Clean Air Act.
CAA section 129 requires EPA to review and, if necessary, add provisions to ensure the
standards adequately protect public health and the environment. Thus, combustion by-products
from incineration treatment of methylene chloride wastes would be subject to these regulations,
as would methylene chloride burned for energy recovery. See 40 CFR part 60.
EPA is not evaluating on-site releases to land that go to underground injection or associated
exposures to the general population or terrestrial species in its risk evaluation. Environmental
disposal of methylene chloride injected into Class I hazardous well types are covered under the
jurisdiction of RCRA and SDWA and disposal of methylene chloride via underground injection
is not likely to result in environmental and general population exposures. See 40 CFR part 144.
EPA is not evaluating on-site releases to land from RCRA Subtitle C hazardous waste landfills
or exposures of the general population or terrestrial species from such releases in the TSCA
evaluation. Design standards for Subtitle C landfills require double liner, double leachate
collection and removal systems, leak detection system, run on, runoff, and wind dispersal
controls, and a construction quality assurance program. They are also subject to closure and post-
closure care requirements including installing and maintaining a final cover, continuing
operation of the leachate collection and removal system until leachate is no longer detected,
maintaining and monitoring the leak detection and groundwater monitoring system. Bulk liquids
may not be disposed in Subtitle C landfills. Subtitle C landfill operators are required to
implement an analysis and testing program to ensure adequate knowledge of waste being
managed, and to train personnel on routine and emergency operations at the facility. Hazardous
waste being disposed in Subtitle C landfills must also meet RCRA waste treatment standards
before disposal. See 40 CFR part 264; Appendix A.
EPA is not evaluating on-site releases to land from RCRA Subtitle D municipal solid waste
(MSW) landfills or exposures of the general population or terrestrial species from such releases
in the TSCA evaluation. While permitted and managed by the individual states, municipal solid
waste landfills are required by federal regulations to implement some of the same requirements
as Subtitle C landfills. MSW landfills generally must have a liner system with leachate collection
and conduct groundwater monitoring and corrective action when releases are detected. MSW
landfills are also subject to closure and post-closure care requirements, and must have financial
assurance for funding of any needed corrective actions. MSW landfills have also been designed
to allow for the small amounts of hazardous waste generated by households and very small
quantity waste generators (less than 220 lbs per month). Bulk liquids, such as free solvent, may
not be disposed of at MSW landfills. See 40 CFR part 258.
Page 62 of 753

-------
EPA is not evaluating on-site releases to land from industrial non-hazardous waste and
construction/demolition waste landfills or associated exposures to the general population or
terrestrial species in the methylene chloride risk evaluation. Industrial non-hazardous and
construction/demolition waste landfills are primarily regulated under authorized state regulatory
programs. States must also implement limited federal regulatory requirements for siting,
groundwater monitoring and corrective action and a prohibition on open dumping and disposal
of bulk liquids. States may also establish additional requirements such as for liners, post-closure
and financial assurance, but are not required to do so. See, e.g., RCRA section 3004(c), 4007; 40
CFR part 257.
Page 63 of 753

-------
1.4.3 Conceptual Models
The conceptual model in Figure 1-2 presents the exposure pathways, exposure routes and hazards to human receptors from industrial
and commercial activities and uses of methylene chloride.
INDUSTRIAL AND COMMERCIAL	EXPOSURE PATHWAY	EXPOSURE ROUTE	RECEPTORS'1	HAZARDS
ACTIVITIES / USES
Manufacturing
Processing:
	Incorporated into
Formulation, Mixture, or
Reaction Product
	Repackaging
Liquid Contact
Hazards Potentially Associated
with Acute and/or Chronic
Exposures
Workerse
Recycling
Solvents for Cleaning or
Degreasing
Vapor/ Mist
Occupational
Inhalation'
Fugitive
Emissions'1
Paints and Coatings
including Paints and
Coatings Removers
Fabric, Textile, and
Leather Products
Apparel and Footwear
Care Products
Laundry and Dishwashing
Lubricants and Greases
Waste Handling,
Treatment and Disposal
~ Wastewater or Liquid Wastes
Figure 1-2. Methylene Chloride Conceptual Model for Industrial and Commercial Activities and Uses: Potential Exposure and
Hazards
a Some products are used in both commercial and consumer applications such adhesives and sealants. Additional uses of methylene chloride are included in
Table 1-4.
b Fugitive air emissions are those that are not stack emissions and include fugitive equipment leaks from valves, pump seals, flanges, compressors, sampling
connections and open-ended lines; evaporative losses from surface impoundment and spills; and releases from building ventilation systems.
0 Exposure may occur through mists that deposit in the upper respiratory tract. However, based on physical chemical properties, mists of methylene chloride will
likely be rapidly absorbed in the respiratory tract or evaporate, and were evaluated as an inhalation exposure.
d Receptors include PESS.
e When data and information were available to support the analysis, EPA also considered the effect that engineering controls and/or personal protective
equipment (PPE) have on occupational exposure levels.
Page 64 of 753

-------
The conceptual model in Figure 1-3 presents the exposure pathways, exposure routes and hazards to human receptors from consumer
activities and uses of methylene chloride.
CONSUMER ACTIVITIES / USES	EXPOSURE PATHWAY	EXPOSURE ROUTE	RECEPTORS'3	HAZARDS
Liquid Contact
Solvents for Cleaning and
Degr easing
Fabric, Textile, and Leather
Paints and Coatings Excluding
Paint and Coating Removers
Hazards Potentially
with Acute and/or
Exposures
KEY:
Uses, pathways and receptors that were
not further analyzed
Pathways that were not further analyzed.
Pathways that were not further analyzed.
Figure 1-3. Methylene Chloride Conceptual Model for Consumer Activities and Uses: Potential Exposure and Hazards
a Some products are used in both commercial and consumer applications. Additional uses of methylene chloride are included in Table 1-4.
b Receptors include PESS.
0 Exposure may occur throughs mists that deposit in the upper respiratory tract or via transfer of methylene chloride from hand to mouth. However, this exposure
pathway will be limited by a combination of rapid absorption and/or evaporation that will not result in oral exposure. Therefore, this pathway will not be further
evaluated.
The conceptual model in Figure 1-4 presents the exposure pathways, exposure routes and hazards to human and enviromnental receptors from enviromnental
releases and wastes of methylene chloride.
Page 65 of 753

-------
RELEASES AND WASTES FROM
INDUSTRIAL / COMMERCIAL USES
EXPOSURE PATHWAY
RECEPTORS
HAZARDS
Direct
discharge
Aquatic
Species
Sediment
Terrestrial
Species
Biosolids
Soil
POTW
Wastewater or
Liquid Wastes3
Industrial Pre-
Treatment or
Industrial WWT
Hazards Potentially Associated with
Acute and Chronic Exposures
Figure 1-4. Methylene Chloride Conceptual Model for Environmental Releases and Wastes: Potential Exposures and Hazards
a Industrial wastewater may be treated on-site and then released to surface water (direct discharge), or pre-treated and released to POTW (indirect discharge).
Page 66 of 753

-------
1.5 Systematic Review
TSCA requires EPA to use scientific information, technical procedures, measures, methods,
protocols, methodologies and models consistent with the best available science when making
science-based decisions under Section 6 and base decisions under Section 6 on the weight of
scientific evidence. Within the TSCA risk evaluation context, the weight of the scientific
evidence is defined as "a systematic review method, applied in a manner suited to the nature of
the evidence or decision, that uses a pre-established protocol to comprehensively, objectively,
transparently, and consistently identify and evaluate each stream of evidence, including
strengths, limitations, and relevance of each study and to integrate evidence as necessary and
appropriate based upon strengths, limitations, and relevance" (40 CFR 702.33).
To meet the TSCA  26(h) science standards, EPA used the TSCA systematic review process
described in the Application of Systematic Review in TSCA Risk Evaluations document (
EPA. 2018b). The process complements the risk evaluation process in that the data collection,
data evaluation and data integration stages of the systematic review process are used to develop
the exposure and hazard assessments based on reasonably available information. EPA defines
"reasonably available information" to mean information that EPA possesses, or can reasonably
obtain and synthesize for use in risk evaluations, considering the deadlines for completing the
evaluation (40 CFR 702.33).
EPA is implementing systematic review methods and approaches within the regulatory context
of the amended TSCA. Although EPA adopted as many best practices as practicable from the
systematic review community, EPA modified the process to ensure that the identification,
screening, evaluation and integration of data and information can support timely regulatory
decision making under the timelines of the statute.
1.5.1 Data and Information Collection
EPA planned and conducted a comprehensive literature search based on key words related to the
different discipline-specific evidence supporting the risk evaluation (e.g., environmental fate and
transport; environmental releases and occupational exposure; exposure to general population,
consumers and environmental exposure; and environmental and human health hazard). EPA then
developed and applied inclusion and exclusion criteria during the title/abstract screening to
identify information potentially relevant for the risk evaluation process. The literature and
screening strategy as specifically applied to methylene chloride is described in Strategy for
Conducting Literature Searches for Methylene Chloride (DCM): Supplemental File to the TSCA
Scope Document (U.S. EPA. 2 ) and the results of the title and abstract screening process
were published in Methylene Chloride (DCM) (CASRN: 75-09-2) Bibliography: Supplemental
File for the TSCA Scope Document (U.S. EPA. 2017a).
For studies determined to be on-topic (or relevant) after title and abstract screening, EPA
conducted a full text screening to further exclude references that were not relevant to the risk
evaluation. Screening decisions were made based on eligibility criteria documented in the form
of the populations, exposures, comparators, and outcomes (PECO) framework or a modified
Page 67 of 753

-------
framework7. Data sources that met the criteria were carried forward to the data evaluation stage.
The inclusion and exclusion criteria for full text screening for methylene chloride are available in
in Appendix F of Problem Formulation of the Risk Evaluation for Methylene Chloride
(Dichloromethane, DCM) (	).
In addition to the comprehensive search and screening process conducted as described above,
EPA made the decision to leverage the literature published in previous assessments8 to identify
key and supporting data9 and information for developing the methylene chloride risk evaluation.
This is discussed in Strategy for Conducting Literature Searches for Methylene Chloride (DCM):
Supplemental File to the TSCA Scope Document (	D17d). In general, many of the key
and supporting data sources were identified in the comprehensive Methylene Chloride (DCM)
(CASRN: 75-09-2) Bibliography: Supplemental File for the TSCA Scope Document (U.S. EPA.
2017a). However, there was an instance during the releases and occupational exposure data
search for which EPA missed relevant references that were not captured in the initial
categorization of the on-topic references. EPA found additional relevant data and information
using backward reference searching, which was a technique that will be included in future search
strategies. This issue is discussed in Section 4 of Application of Systematic Review for TSCA Risk
Evaluations (U.S. EPA. 2018b). Other relevant key and supporting references were identified
through targeted supplemental searches to support the analytical approaches and methods in the
methylene chloride risk evaluation (e.g., to locate specific information for exposure modeling).
EPA used previous chemical assessments to quickly identify relevant key and supporting
information as a pragmatic approach to expedite the quality evaluation of the data sources, but
many of those data sources were already captured in the comprehensive literature as explained
above. EPA also considered newer information not taken into account by previous chemical
assessments as described in Strategy for Conducting Literature Searches for Methylene Chloride
(DCM): Supplemental File to the TSCA Scope Document (U.S. EPA.: ). EPA then
evaluated the confidence of the key and supporting data sources as well as newer information
instead of evaluating the confidence of all the underlying evidence ever published on a chemical
substance's fate and transport, environmental releases, environmental and human exposure and
hazards. Such comprehensive evaluation of all of the data and information ever published for a
chemical substance would be extremely labor intensive and could not be achieved under the
TSCA statutory deadlines for most chemical substances especially those that have a data-rich
database. Furthermore, EPA considered how evaluation of newer information in addition to the
key and supporting data and information would change the conclusions presented in previous
assessments.
7	A PESO statement was used during the full text screening of environmental fate and transport data sources. PESO
stands for Pathways and Processes, Exposure, Setting or Scenario, and Outcomes. A RESO statement was used
during the full text screening of the engineering and occupational exposure literature. RESO stands for Receptors,
Exposure, Setting or Scenario, and Outcomes.
8	Examples of existing assessments are EPA's chemical assessments (e.g., previous work plan risk assessments,
problem formulation documents), ATSDR's Toxicological Profiles and EPA's IRIS assessments. This is described
in more detail in Strategy for Conducting Literature Searches for Methylene Chloride (DCM): Supplemental File
to the TSCA Scope Document (U.S. EPA, 2017d).
9	Key and supporting data and information are those that support key analyses, arguments, and/or conclusions in the
risk evaluation.
Page 68 of 753

-------
Figure 1-5 to Figure 1-9 depict literature flow diagrams illustrating the results of this process for
each scientific discipline-specific evidence supporting the risk evaluation. Each diagram
provides the total number of references at the start of each systematic review stage (i.e., data
search, data screening, data evaluation, data extraction/data integration) and those excluded
based on criteria guiding the screening and data quality evaluation decisions.
EPA made the decision to bypass the data screening step for data sources that were highly
relevant to the risk evaluation as described above. These data sources are depicted as
"key/supporting data sources" in the literature flow diagrams. Note that the number of
"key/supporting data sources" were excluded from the total count during the data screening stage
and added, for the most part, to the data evaluation stage depending on the discipline-specific
evidence. The exception was the releases and occupational exposure data sources that were
subject to a combined data extraction and evaluation step (Figure 1-6).
The number of publications considered in each step of the systematic review of methylene
chloride for environmental fate and transport literature is summarized in Figure 1-5.
Data Evaluation (n=47)
"Key/Supporting
Data Sources (n=l'
Data Search Results (n=7,216)
Data Screening (n--7,216'
Data Extraction/Data Integration (n=43)
Excluded References
(n=7,170)
Excluded: Ref that are
unacceptable based on the
evaluation criteria (n=4)
"This is a key and supporting source from existing assessments, the EPI Suite set of models, that was highly relevant
for the TSCA risk evaluation. This source bypassed the data screening step and moved directly to the data evaluation
step.
Figure 1-5. Literature Flow Diagram for Environmental Fate and Transport Data Sources
Note: Literature search results for the environmental fate and transport of methylene chloride yielded 7,216 studies.
During problem formulation, following data screening, most environmental exposure pathways were removed from
the conceptual models. As a result, 7,170 studies were deemed off-topic and excluded. One key source and the
remaining 46 studies related to environmental exposure pathways retained in the conceptual models entered data
evaluation, where 4 studies were deemed unacceptable and 43 moved into data extraction and integration.
Page 69 of 753

-------
The number of publications considered in each step of the systematic review of methylene
chloride for releases and occupational exposure literature is summarized in Figure 1-6.
Data Starch Results ^n=?,484j
Data Screening (7484)
Excluded References
imlMJ)
n=tST
Key/supporting
data sources
(ft=23)
Data Extraction.Data Evaluation fn=180}
I
Excluded: Re? mat are
unacceptable based on
{n=36H
'Data Sources mat were not
integrated (v=99)
The quality of tfata in these sources were acceptable for risk evaluation purposes, but they
were ultimately excluded from further consideration based on CPA's integration approach fsr
environmental release and occupational exposure data/information. ERA'S spproaeff uses a werarcfiy
of preferences that guide decisions about what types of data/information m ineiwfeci for further
analysts, synthesis and integration into the environmental release ana occupational exposure
assessments. EPA prefers using fiats with the highest rated quality among (hose  the higher level of
the hierarchy of preferences (i.e.. data > modeling  occupational exposure limns or release limits). If
warranted, EPA may use data/information of lower rated qualify as supportive evidence # the
environmental release and occupational exposure assessments.
Figure 1-6. Releases and Occupational Exposures Literature Flow Diagram for Methylene
Chloride
Note: Literature search results for environmental release and occupational exposure yielded 7,484 data sources. Of these data
sources, initially 268 were determined to be relevant for the risk evaluation through the data screening process. Due to the scope
changing the initial 268 data sources were reevaluated and it was determined 157 data sources to be relevant for the risk
evaluation through the data screening process. These relevant data sources were entered into the data extraction/evaluation phase.
After data extraction/evaluation, EPA identified several data gaps and performed a supplemental, targeted search to fill these
gaps (e.g., to locate information needed for exposure modeling). The supplemental search yielded 23 relevant data sources that
bypassed the data screening step and were evaluated and extracted in accordance with Appendix D of Data Quality Criteria for
Occupational Exposure and Release Data of the Application of Systematic Review for TSCA Risk Evaluations document (TJ.S.
EPA, 2018b). Of the 179 sources from which data were extracted and evaluated, 36 sources only contained data that were rated
as unacceptable based on serious flaws detected during the evaluation. Of the 143 sources forwarded for data integration, data
from 45 sources were integrated, and 99 sources contained data that were not integrated (e.g., lower quality data that were not
needed due to the existence of higher quality data, data for release media that were removed from scope after data collection).
The data integration strategy for releases and occupational exposure data is discussed in Appendix G of the document titled "Risk
Evaluation for Methylene Chloride (Dichloromethane, DCM) CASRN: 75-09-2, Supplemental Information on Releases and
Occupational Exposure Assessment"(EPA, 2019b).
Page 70 of 753

-------
The number of publications considered in each step of the systematic review of methylene
chloride for non-occupational exposure literature is summarized in Figure 1-7.
Excluded References (n = 382)
Data Extra ctioa'Data Integration (n - 44)
Data Evaluation (n - 89)
Data Screening (n - 471)
Data Search Results (n = 4711
Excluded References frt = 45)
Unacceptable based on dots evaluation criteria {n = 5}
Not primary source, notextractable or
not most relevant (n - 401
The quality of data in these sources were acceptable for risk evaluation purposes and considered tor
integration. The sources; however, were not extracted for a variety of reasons, such as they contained only
secondary source data, duplicate data, or non-extractabte data {i.e., charts or figures). Additionally, some
data sources were not as relevant to the PECO as other data sources which were extracted.
Figure 1-7. Literature Flow Diagram for General Population, Consumer and
Environmental Exposure Data Sources
Note: EPA conducted a literature search to determine relevant data sources for assessing exposures for methylene
chloride within the scope of the risk evaluation. This search identified 471 data sources including relevant
supplemental documents. Of these, 382 were excluded during the screening of the title, abstract, and/or full text and
89 data sources were recommended for data evaluation across up to five major study types in accordance with
Appendix E: Data Quality Criteria for Studies on Consumer, General Population and Environmental Exposure of
the Application of Systematic Review for TSCA Risk Evaluations document. (U.S. EPA, 2018b). Following the
evaluation process, 44 references were forwarded for further extraction and data integration.
The conceptual model for environmental exposures was modified during problem formulation,
which changed 63 previously on-topic references to off-topic between data screening and data
evaluation, leaving 79 publications in the data evaluation stage.
Page 71 of 753

-------
The number of publications considered in each step of the systematic review of methylene
chloride for environmental hazard literature is summarized in Figure 1-8.
Data Search Results (n = 4930}
Title/Abstract Screening (n = 4929)
Foil Text Screening {o = 224)
Ex*
Data Evaluation (n = 45}
'PS

Data Extraction! Data Integration (n = 14]
Figure 1-8. Literature Flow Diagram for Environmental Hazard Data Sources
Note: The environmental hazard data sources were identified through literature searches and screening strategies
using the ECOTOXicology Knowledgebase System (ECOTOX) Standing Operating Procedures. For studies
determined to be on-topic after title and abstract screening, EPA conducted a Ml text screening to further exclude
references that were not relevant to the risk evaluation. Screening decisions were made based on eligibility criteria
as documented in the ECOTOX User Guide (EPA. 2018b')'). Additional details can be found in the Strategy for
Conducting Literature Searches for Methylene Chloride Supplemental Document to the TSCA Scope Document
(U.S. EPA. 20ndl.
The "Key/Supporting Studies" box represents data sources typically cited in existing assessments and considered
highly relevant for the TSCA risk evaluation because they were used as key and supporting information by
regulatory and non-regulatory organizations to support their chemical hazard and risk assessments. These citations
were found independently from the ECOTOX process. These studies bypassed the data screening step and moved
directly to the data evaluation step.
Studies could be considered "out of scope" after the screening steps, and therefore excluded from data evaluation,
due to the elimination of pathways during scoping/problem formulation.
Page 72 of 753

-------
The number of publications considered in each step of the systematic review of methylene
chloride for human health hazard literature is summarized in Figure 1-9.
Excluded References {n = 7294)
n= 36
Data Searching fn = T422)
Data Extraction;Data Integration (rt = 113}
Excluded: Ref that are
unacceptable based on
evatuation criteria (n = 15)
Dala Evaluation (n = 128}
Data Screening (n = 7330)
Figure 1-9. Literature Flow Diagram for Human Health Hazard Data Sources
Note: Literature search results for human health hazard of methylene chloride yielded 7,422 studies. This included
92 key and supporting studies identified from previous EPA assessments. Of the 7,330 new studies screened for
relevance, 7,294 were excluded as off topic. The remaining 36 new studies and 92 key/supporting studies were
evaluated for data quality. Fifteen studies were deemed unacceptable based on the evaluation criteria of human
health hazard and the remaining 113 studies were carried forward to data extraction/data integration.
Page 73 of 753

-------
2 EXPOSURES
2.1 Fate and Transport	
Environmental fate includes both environmental transport and transformation processes.
Environmental transport is the movement of the chemical within and between environmental
media. Transformation occurs through the degradation or reaction of the chemical in the
environment. Hence, understanding the environmental fate of methylene chloride informs the
determination of the specific exposure pathways, and potential human and environmental
receptors which EPA considered in its risk evaluation.
2.1.1 Fate and Transport Approach and Methodology
EPA gathered and evaluated environmental fate information according to the process described
in the Application of Systematic Review in TSCA Risk Evaluations (U.S. EPA. 2018a).
Reasonably available environmental fate data, including biotic and abiotic degradation rates,
removal during wastewater treatment, volatilization from lakes and rivers, and an organic
carbon:water partition coefficient (Koc) were selected for use in the current evaluation.
Sufficient numbers of high-confidence biodegradation studies were available, so it was not
necessary to use lower-quality data for that endpoint; thus, in assessing the environmental fate
and transport of methylene chloride, EPA considered the full range of results from sources that
were rated high confidence. Complete data extraction tables are available in the supplemental file
Data Extraction Tables for Environmental Fate and Transport Studies (EPA. 2019e) and
complete data evaluation information is available in the supplemental fileData Quality
Evaluation of Environmental Fate and Transport Studies (	319D.
Other fate estimates were based on modeling results from EPI (Estimation Programs Interface)
Suite (	12), a predictive tool for physical/chemical and environmental fate
properties (https://www.epa.gov/tsca-screening-tools/epi-suitetm-estimation-program-
interface). Information regarding the EPI Suite model inputs is available in Appendix C and
model outputs are available in the supplemental file Data Extraction Tables for Environmental
Fate and Transport Studies (EPA. 2019e). EPI Suite was reviewed by the EPA Science
Advisory Board
(http://YOsemite.epa.gov/sab/sabprodiict.nsf/02ad90bl36fc21efij5256eba00436459/CCF98z
F9CFCFA8525735200739805/$File/i	f) and the individual models have been peer-
reviewed in numerous articles published in technical journals. Citations for such articles are
available in the EPI Suite help files.
Table 2-1 provides environmental fate data that EPA considered while assessing the fate of
methylene chloride. The data in Table 2-1 were updated after problem formulation with
information identified through systematic review.
Page 74 of 753

-------
Table 2-1. Environmental Fate Characteristics of Methylene Chloride
Property or
Kmlpoinl
Value11
References
Data Quality
Rating
Indirect
photodegradati on
half-life
79 days (atmospheric oxidation by
reaction with hydroxyl radicals
[OH]; estimated)13
U.S. EPA. (2012)
High
97 days (atmospheric oxidation by
reaction with *OH; estimated)0
(Mansouri et al.. 2018)
High
Hydrolysis half-
life
18 months
Dillina et al. (1975)
High
4.3xl07 yrs (estimated)13
>012)
High
Aerobic
Biodegradation
0% in 28 days (activated sludge)
Laoertot and Pulsarin
(2006)
High
100% in 7 days (activated sludge)
Tabak et al. (1981)
High
90% in 6 days (marine water)
Krausova et al. (2006)
High
Anaerobic
Biodegradation
58%) in 30 hrs (pre-adapted
culture)
Braus-Stromever et al.
(1993)
High
65-84% in 31 hrs (sediment)
Melin et al. (1996)
High
Approx. 75%) in 22 days
(sediment)
Peiimemburg et i 8)
High
100%o in 10 days (digested sludge)
Goss S5)
High
Bioconcentration
factor (BCF)
3.1 (estimated by linear regression
from octanol-water partition
coefficient)13
2.6 (estimated by Arnot-Gobas
quantitative structure-activity
relationship [QSAR])b
> i r \ t >ot:>
High
Bioaccumulation
factor (BAF)
<1 - 577 (measured in lentic
ecosystem microcosm)
Thiebaud et 94)
High
2.6 (estimated by Arnot-Gobas
QSAR)b

High
15.1 (estimated)0
(Mansouri et al.. 2018)
High
log Koc
1.34 (estimated from molecular
connectivity index)b
1.08 (estimated from log Kow)b
>012)
High
1.5 (estimated)0
(Mansouri et al.. 2018)
High
a Measured unless otherwise noted.
b Information was estimated usins EPI Suite ("U.S. EPA. 2012)
0 Information was estimated using OPERA (Mansouri et at. 2018)
Page 75 of 753

-------
2.1.2 Summary of Fate and Transport
The EPI Suite (	) model that predicts removal in wastewater treatment
(STPWIN; see Appendix C for information regarding inputs used for EPI Suite) estimated that
< 1% of methylene chloride in influent water will be removed via sorption to sludge. The organic
water-carbon partition coefficient (log Koc) is estimated to be 1.4, which is associated with low
sorption to sludge, soil, and sediment. Due to its Henry's Law constant (0.00325 atm-m3/mole),
methylene chloride is expected to volatilize rapidly from water; STPWIN estimated that
approximately 56% of methylene chloride in influent would be removed by volatilization to the
air. Reported aerobic biodegradation rates are mixed, ranging from slow (e.g., negligible
degradation in 28 days) to fast (e.g., complete degradation in 7 days) (Krausova et at.. 2006;
Lapertot and Pulgarin. 2006; Tabak et at. 1981). so overall removal of methylene chloride from
wastewater treatment is expected to range from 57% (based on STPWIN estimates for
volatilization to air and sorption to sludge, with negligible biodegradation) to complete (based on
volatilization, sorption, and high biodegradation). The low end of this range is similar to the
methylene chloride removal efficiency (54%) reported by the EPA Toxics Release Inventory
(TRI) (	017fi.
Based on the results of the STPWIN model, in which removal of methylene chloride from
wastewater is dominated by volatilization, in combination with possible biodegradation,
concentrations of methylene chloride in land-applied biosolids are expected to be lower than
concentrations in wastewater treatment plant effluents. Methylene chloride has been detected in
biosolids [e.g., ]	)] however land-applied biosolids are spread over a large area and
diluted in runoff and surface water. Level III fugacity modeling as implemented in EPI Suite
using 100%) emission to soil as a proxy for land application of biosolids estimates that 58% of
methylene chloride volatilizes to air, 38% remains in soil, and 3% is transported to water.
However, the model assumes constant emissions rather than a pulse as land application of
biosolids would be; thus, those model results likely overstate how much methylene chloride
would remain in soil. Overall, based on p-chem and fate properties and the results of fugacity
modeling, surface and drinking water exposures from land-applied biosolids are likely
negligible.
Based on its low partitioning to organic matter and rapid biodegradation in anaerobic
environments (Peiinenburg et ai. 1998; Melin et al. 1996; Braus-Stromever et al.. 1993; Gossett.
1985). methylene chloride is expected to be present in sediments at concentrations similar to or
lower than those of the overlying water. Although the log Koc indicates that methylene chloride
will partition to sediment organic carbon, organic matter typically comprises 25% or less of
sediment composition (e.g., https://pubs.usgs.gov/of/2006/1053/downloads/pdf/of-20Q6-
l) of which approximately 40-60% is organic carbon (Schwarzenbach et al.. 2003). Thus,
the fraction of organic carbon (foe) in soil is typically 0.15 or less. Based on these values, the
sediment-water Kd (where Kd = Koc*/oc) is expected to be equal to or less than 3.8, indicating
that at equilibrium, concentrations in sediment would be expected to be less than four times
higher than in porewater. However, methylene chloride concentrations in sediment are expected
to be depressed by rapid biodegradation in anaerobic sediments and porewater interaction with
overlying surface water. Thus, concentrations in sediment and pore water are expected to be
similar to or less than concentrations in overlying water.
Page 76 of 753

-------
Due to its high Henry's Law constant and vapor pressure (435 mmHg at 25C), methylene
chloride is expected to volatilize from surface water and soil. The EPI Suite module that
estimates volatilization from lakes and rivers (water volatilization model) was run using default
settings to evaluate the volatilization half-life of methylene chloride in surface water and
estimated that the half-life of methylene chloride in a model river will be 1.1 hours and the half-
life in a model lake will be less than 4 days. In the atmosphere, methylene chloride will slowly
react with hydroxyl radicals (*OH), with an indirect photolysis half-life of 79 days. Due to its
persistence, methylene chloride is expected to be subject to local and long-range atmospheric
transport. Based on its vapor density (2.93 relative to air), volatilized methylene chloride is
expected to remain near ground level in very calm conditions, but with mixing will readily
disperse into the air.
Although methylene chloride released to the environment is likely to evaporate to the
atmosphere, due to its low partitioning to organic matter it may migrate to groundwater. Indeed,
detections of methylene chloride in groundwater have been reported (e.g., in the EPA's Water
Quality portal, http://www.waterqualitvdata.us/portal.isp; reports of detection in groundwater did
not go through data evaluation and extraction because groundwater pathways are outside the
scope of this risk evaluation). In groundwater, methylene chloride may slowly hydrolyze.
The bioconcentration potential of methylene chloride is low; the EPI Suite BCFBAF model
estimates bioconcentration factors of 2.6 to 3.1 and a bioaccumulation factor of 2.6 (U.S. EPA
2012). and a study of bioaccumulation in a lentic microcosm reported radioactivity accumulation
factors ranging from <1 to 577 (Thiebaud et al.. 1994).
Overall, methylene chloride is expected to have limited accumulation potential in wastewater
biosolids, soil, sediment, and biota. Methylene chloride released to surface water or soil is likely
to volatilize to the atmosphere, where it will slowly photooxidize. Methylene chloride may
migrate to groundwater, where it may be removed via anaerobic biodegradation or slowly
hydrolyze. Figure 2-1 summarizes the overall environmental partitioning and degradation
expected for methylene chloride.
log KoC = 1.4
Groundwater
Aerobic Biodegradation p?p
Rate = slow to rapid
Hydrolysis
t1/2 > 18 months
Anaerobic Biodegradation
Rate = rapid
Surface Water
log Kqc = 1.4
^ ~
 Sediment
Land-applied biosolids
Bioaccumu ation
BAF < 577
 Photolysis
ti/2 = 79-97 days
Figure 2-1 Environmental transport, partitioning, and degradation processes for methylene
chloride.
Page 77 of 753

-------
In Figure 2-1, transport and partitioning are indicated by green arrows and degradation is
indicated by orange arrows. The width of the arrow is a qualitative indication of the likelihood
that the indicated partitioning will occur or the rate at which the indicated degradation will occur
(i.e., wider arrows indicate more likely partitioning or more rapid degradation). The question
marks over the aerobic biodegradation arrow indicate uncertainty regarding how quickly
methylene chloride will biodegrade. Although transport and partitioning processes (green
arrows) can occur in both directions, the image illustrates the primary direction of transport
indicated by partition coefficients. Figure 2-1 considers only transport, partitioning, and
degradation within and among environmental media; sources to the environment such as
discharge and disposal are not illustrated.
2.1.3 Key Sources of Uncertainty in Fate and Transport Assessment
The experimentally determined methylene chloride biodegradation rates in aerobic environments
ranged from slow to rapid (see Table 2-1). The fastest degradation was reported by Tabak et al.
(JOSI), who measured 100% degradation in 7 days. Conversely, Lapertot and Pulgarin (2006)
reported 0% degradation in 28 days with the explanation that methylene chloride was causing
cell lysis. Cell lysis may not have been observed by Tabak et al. ( ) because methylene
chloride was spiked into their test vessels at concentrations 5-10 times lower than those used by
Lapertot and Pulgarin (2006) (5-10 mg/L versus 50 mg/L).
Methylene chloride biodegradation data reported to foreign governments demonstrate similar
discrepancies. Data submitted to Japanese National Institute of Technology and Evaluation
reported <13% of methylene chloride degraded after 28 days from an initial concentration of 100
mg/L, whereas data submitted to the European Chemicals Agency showed that 68% of
methylene chloride was removed in 28 days from an initial concentration of 5 mg/L.
For comparison, the EPI Suite module that predicts biodegradation rates ("BIOWIN" module)
was run using default settings to estimate biodegradation rates of methylene chloride. The
BIOWIN models for aerobic environments (BIOWIN 1-6) estimate that methylene chloride will
not rapidly biodegrade in aerobic environments. In agreement with the experimental data for
anaerobic biodegradation of methylene chloride, the BIOWIN model of anaerobic
biodegradation (BIOWIN 7) predicts that methylene chloride will biodegrade rapidly under
anaerobic conditions. Overall, methylene chloride biodegradation rates in aerobic environments
may vary based on factors including microorganism consortia present and microorganisms'
previous exposure and adaptation to methylene chloride or other halogenated substances. This
uncertainty in biodegradation rates was considered in the assessment of environmental
persistence.
The uncertainty around aerobic biodegradation rates also impacts estimates of removal from
wastewater. As described in Section 2.1.2, the STPWIN module of EPI Suite estimates that
57%) of methylene chloride in influent wastewater will be removed via sorption to sludge or
volatilization to air. Biodegradation rates in activated sludge and settled biosolids are dependent
on factors such as the microbial consortia present, their previous adaptation to methylene
chloride, and the biomass concentrations in activated sludge stage. Thus, biodegradation in
WWTP may range from negligible to complete, resulting in overall removal estimates of 57%> be
abiotic processes alone to complete via abiotic and biotic removal processes.
Page 78 of 753

-------
2.2 Releases to the Environment
2.2.1 Water Release Assessment Approach and Methodology
EPA performed a literature search to identify process operations that could potentially result in
direct or indirect discharges to water for each condition of use. Where available, EPA used 2016
Toxics Release Inventory (TRI) (	2Q17D and 2016 Discharge Monitoring Report
(DMR) (EPA. 2016) data to provide a basis for estimating releases. Facilities are only required to
report to TRI if the facility has 10 or more full-time employees, is included in an applicable
North American Industry Classification System (NAICS) code, and manufactures, processes, or
uses the chemical in quantities greater than a certain threshold (25,000 pounds for manufacturers
and processors of methylene chloride and 10,000 pounds for users of methylene chloride). Due
to these limitations, some sites that manufacture, process, or use methylene chloride may not
report to TRI and are therefore not included in these datasets.
For the 2016 DMR, EPA used the Water Pollutant Loading Tool within EPA's Enforcement and
Compliance History Online (ECHO), https://echo.epa.gov/trends/loading-tool/water-pollution-
search/. to query all methylene chloride point source water discharges in 2016. DMR data are
submitted by National Pollutant Discharge Elimination System (NPDES) permit holders to states
or directly to the EPA according to the monitoring requirements of the facility's permit. States
are only required to load major discharger data into DMR and thus, may or may not load minor
discharger data. The definition of major vs. minor discharger is set by each state and could be
based on discharge volume or facility size. Due to these limitations, some sites that discharge
methylene chloride may not be included in the DMR dataset.
Facilities reporting releases in TRI and DMR also report associated NAICS and Standard
Industrial Classification (SIC) industry codes, respectively. Where possible, EPA reviewed the
NAICS and SIC descriptions for each reported release and mapped each facility to a potential
condition of use associated with occupational exposure scenarios (OES, see Table 2-22). For
facilities that did not report a NAICS or SIC code, EPA performed a supplemental internet
search of the specific facility to determine the mapping. Facilities that could not be mapped were
grouped together into an "Other" category.
When possible for each OES covering conditions of use, EPA estimated annual releases, average
daily releases, and number of release days/yr. Where TRI and/or DMR were available, EPA used
the reported annual releases for each site and estimated the daily release by averaging the annual
release over the estimated release days/yr. Where releases are expected but TRI and DMR data
were not available, EPA included a qualitative discussion of potential release sources.
EPA did not locate data on number of release days/yr for facilities. The following guidelines
were used to estimate the number of release days/yr:
 Manufacturing: For the manufacture of the solvents with large production volumes, EPA
assumes 350 days/yr for release frequency. This frequency assumes that the facility
operates 7 days/week and 50 weeks/yr (with two weeks down for turnaround) and that the
facility is producing and releasing the chemical daily during operation.
Page 79 of 753

-------
	Processing as Reactant: Methylene chloride is used to manufacture other commodity
chemicals, such as refrigerants or other chlorinated compounds, which will likely occur
year-round. Therefore, EPA assumes 350 days/yr for release frequency based on the same
assumptions for Manufacturing.
	Processing into Formulation Product: For these facilities, EPA does not expect that
methylene chloride will be used year-round, even if the facility operates year-round.
Therefore, EPA assumes 300 days/yr for release frequency, which is based on a European
Union SpERC that uses a default of 300 days/yr for release frequency for the chemical
industry (Eefaa. 2013).
	Wastewater Treatment Plants: For these facilities, EPA expects that they will be used
year-round. Therefore, EPA assumes 365 days/yr for release frequency.
	All Other Scenarios: For all other scenarios, EPA does not expect that methylene chloride
will be used year-round and assumes 250 days/yr for release frequency (5 days/week, 50
weeks/yr).
2.2.2 Water Release Estimates by Occupational Exposure Scenario
As noted in the previous section, EPA mapped each facility to a potential condition of use
associated with occupational exposure scenarios (OES, see Table 2-22). Facilities that could not
be mapped were grouped together into an "Other" category. The following sections show release
estimates per facility for each OES. The supplemental document titled " Risk Evaluation for
Methylene Chloride (Dichloromethane, DCM) CASRN: 75-09-2, Supplemental Information on
Releases and Occupational Exposure Assessment" (EPA, 2019b) provides background details on
industries that may use methylene chloride, processes, and numbers of sites for each OES.
2.2.2.1 Manufacturing
EPA assumed that sites under NAICS 325199 (All Other Basic Organic Chemical
Manufacturing) or SIC 2869 (Industrial Organic Chemicals, Not Elsewhere Classified) are
potentially applicable to manufacturing of methylene chloride. These NAICS codes may be
applicable to other conditions of use (processing as a reactant, processingincorporation into
formulation, mixture, or reaction product); however, insufficient information was reasonably
available to make these determinations.
Table 2-2 lists all facilities under these NAICS and SIC codes that reported direct or indirect
water releases in the 2016 TRI or 2016 DMR. Of the potential manufacturing sites listed in CDR,
only one facility was present in Table 2-2, which reported 128 pounds (58 kg) of methylene
chloride transferred off-site to wastewater treatment (Olin Blue Cube, Freeport, TX) (
201 TP. Due to TRI and CDR reporting thresholds, some sites that reported manufacturing
methylene chloride in CDR may not report to TRI, or vice versa. For the sites reporting for this
scenario, the release estimates range from 0.01 to 76 kg/site-yr over 350 days/yr.
Page 80 of 753

-------
Table 2-2. Reported TRI Releases for Organic Chemical Manufacturing Facilities



Aniiiiiil
Aniiiiiil
l);iil\






Rikiisi-
Ri-k-iiu- l);i\s
Ri'k'.isi'
Ri'k'iisi*
Smirivs iS;
Sill- l(k'iuii\
( ii\
SI ;il i-
(k/siu--\ n
(il;i\s/\ I )
(k/sik--d:i>)
\k'ili;i
Niik-s
COVESTRO LLC
BAYTOWN
TX
1
350
0.004
Surface
Water
U.S. EPA
(2017ft
EMERALD
PERFORMANCE
HENRY
IL
0.5
350
0.001
Surface
Water
U.S. EPA
(2017ft
MATERIALS LLC







FISHER SCIENTIFIC
CO LLC
FAIR LAWN
NJ
2
350
0.01
POTW
U.S. EPA
(20170
FISHER SCIENTIFIC
CO LLC
BRIDGEWATER
NJ
2
350
0.01
POTW
U.S. EPA
(2017fi
OLINBLUE CUBE
FREEPORT TX
FREEPORT
TX
58
350
0.2
Non-
POTW
WWT
II. S
QL
EPA
17ft
REGIS
TECHNOLOGIES
INC
MORTON
GROVE
IL
2
350
0.01
POTW
U.S. EPA
(2017ft
SIGMA-ALDRICH






II. S
EPA
MANUFACTURING
SAINT LOUIS
MO
2
350
0.01
POTW
(2017ft
LLC








VANDERBILT





Non-
IIS
EPA
CHEMICALS LLC-
MURRAY
KY
0.5
350
0.001
POTW
(2C
17ft
MURRAY DIV





WWT


EI DUPONT DE








NEMOURS -
CHAMBERS
DEEPWATER
NJ
76
350
0.2
Surface
Water
EPA
(2016"!
WORKS








BAYER





Surface
Water
E
PA
MATERIALSCIENCE
BAYTOWN
TX
10
350
0.03
iM
)16)
BAYTOWN







INSTITUTE PLANT
INSTITUTE
WV
3
350
0.01
Surface
Water

(2(
PA
)16)
MPM SILICONES
LLC
FRIENDLY
WV
2
350
0.005
Surface
Water
E
(2(
PA
)16)
BASF
WEST
AR
1
350
0.003
Surface
E
PA
CORPORATION
MEMPHIS
Water
(2(
)16)
ARKEMA INC
PIFFARD
NY
0.3
350
0.001
Surface
Water
E
(2(
PA
)16)
EAGLE US 2 LLC -
LAKE
CHARLES




Surface
Water
E
PA
LAKE CHARLES
COMPLEX
LA
0.2
350
0.001
(2(
)16)
BAYER
NEW
WV
0.2
350
0.001
Surface
E
PA
MATERIALSCIENCE
MARTINSVILLE
Water
(2(
)16)
ICL-IP AMERICA
GALLIPOLIS
WV
0.1
350
0.0004
Surface
(E
PA.
INC
FERRY
Water
2016)
KEESHANAND





Surface
Water
E
PA
BOST CHEMICAL
MANVEL
TX
0.02
350
0.00005
(2016)
CO., INC.







INDORAMA
VENTURES
SULPHUR
LA
0.01
350
0.00003
Surface
Water
EPA
(2016)
OLEFINS, LLC







CHEMTURA NORTH





Surface
Water
E
PA
AND SOUTH
MORGANTOWN
WV
0.01
350
0.00002
iM
)16)
PLANTS







Page 81 of 753

-------
2.2.2.2 Processing as a Reactant
EPA assumed that sites classified under NAICS 325320 (Pesticide and Other Agricultural
Chemical Manufacturing) or SIC 2879 (Pesticides and Agricultural Chemicals, Not Elsewhere
Classified) are potentially applicable to processing of methylene chloride as a reactant. Table 2-3
lists all facilities under these NAICS and SIC codes that reported direct or indirect water releases
in the 2016 TRI or 2016 DMR. For the sites reporting for this scenario, the release estimates
range from 0.1 to 213 kg/site-yr over 350 days/yr.
Table 2-3. Reported 2016 TRI and DMR Releases for Potential Processing as Reactant
Facilities
Siii- kk-mil\
( il\
SI ;il i-
Aiiiiii;iI
Ri'k'iisi*
(k/sik*-\ r)
Aiimiiil Ri*k*iisi*
l)ii\s (dii\s/\ I )
l);iil\ Ri*k*iisi*
(k/sili*-dii> )
RlllilSl*
Mi-diii
Siiuri i-s 
\iik-s
AMVAC
CHEMICAL CO
AXIS
AL
213
350
0.6
Non-
POTW
WWT
U.S. EPA
THE DOW
CHEMICAL CO
MIDLAND
MI
25
350
0.1
Surface
Water
U.S. EPA
(20170
FMC
CORPORATION
MIDDLEPORT
NY
0.1
350
0.0003
Surface
Water
EPA
(2016"!
2.2.2.3 Processing - Incorporation into Formulation, Mixture, or Reaction Product
EPA identified six NAICS and SIC codes, listed in Table 2-4, that reported water releases in the
2016 TRI and may be related to use as Processing - Incorporation into Formulation, Mixture, or
Reaction Product. Table 2-4 lists all facilities classified under these NAICS and SIC codes that
reported direct or indirect water releases in the 2016 TRI or 2016 DMR. For the sites reporting
for this scenario, the release estimates range from 0.2 to 5,785 kg/site-yr over 350 days/yr.
Table 2-4. Potential Industries Conducting Methylene Chloride Processing - Incorporation
into Formulation, Mixture, or Reaction Product in 2016 TRI or DMR	
NAICS Code
NAICS Description
325180
Other Basic Inorganic Chemical Manufacturing
325510
Paint and Coating Manufacturing
325998
All Other Miscellaneous Chemical Product and Preparation Manufacturing
2819
INDUSTRIAL INORGANIC CHEMICALS
2843
SURF ACTIVE AGENT, FIN AGENTS
2899
CHEMICALS & CHEM PREP, NEC
Table 2-5. Reported 2016 TRI and DMR Releases for Potential ProcessingIncorporation
into Formulation, Mixture, or Reaction Product Facilities	
Silo Iriculilt
Cilj
S(;ilc
Anniiiil
Release
(k*i/si(e-> n
Anniiiil
Release
l);i\s
(d;i\s/> r)
l);iil\
Kclcsisc
(kg/silc-
d;i\)
Kclc.isc
Mi'din
Sources Si
Nulcs
ARKEMA INC
CALVERT
CITY
KY
31
300
0.1
Surface Water
U.S. EPA
(2017:f)
MCGEAN-ROHCO
INC
LIVONIA
MI
113
300
0.4
POTW
U.S. EPA
(2017:f)
Page 82 of 753

-------
Silo Iriciililt
Cilj
Sliilo
Anniiiil
Kclc.isc
(kii/sik'-\ n
Anniiiil
Uck'iiso
l);i\ s
(d;i\s/\ i-)
l);iil\
Kck'.iso
(kg/sili*-
(l:i> )
Koloiiso
Modiii
Sources .V
Noles
WM BARR & CO
INC
MEMPHIS
TN
0.5
300
0.002
POTW
U.S. EPA
(2017:f)
BUCKMAN
LABORATORIES
INC
MEMPHIS
TN
254
300
1
POTW
U.S. EPA
(2017:f)
EUROFINS MWG
OPERON LLC
LOUISVILLE
KY
5,785
300
19
POTW
U.S. EPA
(2017:f)
SOLVAY-
HOUSTON
PLANT
HOUSTON
TX
12
300
0.04
Surface Water
EPA (2016)
HONEYWELL
INTERNATIONAL
INC - GEISMAR
COMPLEX
GEISMAR
LA
4
300
0.01
Surface Water
EPA (2016)
STEP AN CO
MILLSDALE
ROAD
EL WOOD
IL
2
300
0.01
Surface Water
EPAI20J61
ELEMENTIS
SPECIALTIES,
INC.
CHARLESTO
N
WV
0.2
300
0.001
Surface Water
EPA (20.1.6)
2.2.2.4 Repackaging
EPA assumed that sites classified under NAICS 424690 (Other Chemical and Allied Products
Merchant Wholesalers) or SIC 5169 (Chemicals and Allied Products) are potentially applicable
to repackaging of methylene chloride. Table 2-6 lists all facilities in these industries that reported
direct or indirect water release to the 2016 TRI or 2016 DMR. None of the potential repackaging
sites listed in CDR reported water releases to TRI or DMR in reporting year 2016. For the sites
reporting for this scenario, the release estimates range from 0.03 to 144 kg/site-yr over 250
days/yr.
Page 83 of 753

-------
Table 2-6. Reported 2016 TRI ant
DMRRe
eases for Repackaging Facilities
Sill- lik-iilil\
( ii\
Si ale
Annual
Release
(k/site-
yr)
Annual
Release
l)a\s
(ila\s/\ r)
l)ail> Release
(k/siie-ila>)
Release
Media
Si nines
Nules
CHEMI SPHERE
CORP
SAINT LOUIS
MO
2
250
0.01
POTW
U.S. EPA
(2017f)
HUBBARD-
HALL INC
WATERBURY
CT
144
250
1
Non-POTW
WWT
U.S. EPA
(20170
WEBB
CHEMICAL
SERVICE
CORP
MUSKEGON
HEIGHTS
MI
98
250
0.4
POTW
U.S. EPA
(20170
RESEARCH
SOLUTIONS
GROUP INC
PELHAM
AL
0.09
250
0.0003
Surface
Water
EPA (2016")
EMD
MILLIPORE
CORP
CINCINNATI
OH
0.03
250
0.0001
Surface
Water
iMM)
2.2.2.5	Batch Open-Top Vapor Decreasing
EPA did not identify quantitative information about water releases during batch open-top vapor
degreasing (OTVD). The primary source of water releases from OTVDs is wastewater from the
water separator. Water in the OTVD may come from two sources: 1) Moisture in the atmosphere
that condenses into the solvent when exposed to the condensation coils on the OTVD; and/or 2)
steam used to regenerate carbon adsorbers used to control solvent emissions on OTVDs with
enclosures (Durkee. 2014; Kanegsberg and Kanegsberg. 2011; (NIQSH.1, 2002a. b; Niosh.
2002a. b). The water is removed in a gravity separator and sent for disposal ((NIOSH). 2002a. b;
Niosh. 2002a. b). The current disposal practices of the wastewater are unknown; however, a U.S.
EPA (1982) report estimated 20% of water releases from metal cleaning (including batch
systems, conveyorized systems, and vapor and cold systems) were direct discharges to surface
water and 80% of water releases were discharged indirectly to a POTW.
2.2.2.6	Conveyorized Vapor Degreasing
EPA did not identify quantitative information about water releases during vapor degreasing. The
current disposal practices of the wastewater are unknown; however, a U.S. EPA (1982) report
estimated 20% of water releases from metal cleaning (including batch systems, conveyorized
systems, and vapor and cold systems) were direct discharges to surface water and 80% of water
releases were discharged indirectly to a POTW.
2.2.2.7	Cold Cleaning
EPA did not identify quantitative information about water releases during cold cleaning. The
current disposal practices of the wastewater are unknown; however, a U.S. EPA (1982) report
estimated 20% of water releases from metal cleaning (including batch systems, conveyorized
systems, and vapor and cold systems) were direct discharges to surface water and 80% of water
releases were discharged indirectly to a POTW.
Page 84 of 753

-------
2.2.2.8	Commercial Aerosol Products
EPA does not expect releases of methylene chloride to water from the use of aerosol products.
Due to the volatility of methylene chloride the majority of releases from the use of aerosol
products will likely be to air as methylene chloride evaporates from the aerosolized mist and the
substrate surface. There is a potential that methylene chloride that deposits on shop floors during
the application process could possibly end up in a floor drain (if the shop has one) or could
runoff outdoors if garage doors are open. However, EPA expects the potential release to water
from this to be minimal as there would be time for methylene chloride to evaporate before
entering one of these pathways. This is consistent with estimates from the International
Association for Soaps, Detergents and Maintenance Products (AISE) Specific Environmental
Release Categories (SpERC) for Wide Dispersive Use of Cleaning and Maintenance Products,
which estimates 100% of volatiles are released to air (AISE. 2012). EPA expects residuals in the
aerosol containers to be disposed of with shop trash that is either picked up by local waste
management or by a waste handler that disposes shop wastes as hazardous waste.
2.2.2.9	Adhesives and Sealants
Based on a mass balance study on the Dutch use of methylene chloride as adhesives, the
Netherlands Organisation for Applied Scientific Research (TNO) calculated an emission of
100% to air (T>	j99). EPA did not find information on potential water releases.
Water releases may occur if equipment is cleaned with water.
2.2.2.10	Paints and Coatings
EPA did not identify information about potential water releases during application of paints and
coatings. Water releases may occur if equipment is cleaned with water; however, industrial and
commercial sites would likely be expected to dispose of solvent-based paints as hazardous waste.
2.2.2.11	Adhesive and Caulk Removers
EPA did not find specific industry information or release data for use of adhesive and caulk
removers. EPA did not identify quantitative information in the 2016 TRI or 2016 DMR for this
use. Professional contractors who may use adhesive and caulk removers likely do not handle
enough methylene chloride to meet the reporting thresholds of TRI and would not likely report to
DMR because they are not industrial facilities. The majority of methylene chloride is expected to
evaporate into the air, but releases to water may occur if equipment is cleaned with water.
2.2.2.12	Fabric Finishing
EPA did not identify quantitative information about potential water releases during use of
methylene chloride in fabric finishing. The majority of methylene chloride is expected to
evaporate into the air, but releases to water may occur if equipment or fabric is cleaned with
water.
2.2.2.13	Spot Cleaning
The majority of methylene chloride in spot removers is expected to evaporate into the air, but
releases to water may occur if residue remains in the garment during washing. EPA identified
Page 85 of 753

-------
one facility in the 2016 DMR with SIC code 7216 (Drycleaning Plants, Excluding Rug
Cleaning). This facility reported 0.1 kg annual release of methylene chloride to surface water, as
shown in Table 2-7. EPA did not identify any potential spot cleaning facilities in the 2016 TRI
that reported water releases. Other facilities in this industry may not dispose to water or use
methylene chloride in quantities that meet the TRI reporting threshold. For the site reporting for
this scenario, the release estimate is 0.1 kg/site-yr over 250 days/yr.
Table 2-7. Surface Water Releases of Methylene Chloride During Spot Cleaning
Sill- IdinliU
< ii>
Shilc
Aiiiiuill Rclciisc
(k/siic-\ n
Aiimiiil Ri-k-sisi-
l)si\s (d;i>s/\ r)
l);iil\ Riliusi'
(k/sili'-d;i> )
Ri-k-sisi-
Mid in
Sources iS; Niilis
uois]-: s i mi
UNIVERSITY
boisi:
II)
0.1
250
0.0002
Surface
Waler

2,2.2.14 Cellulose Triacetate Film Production
EPA identified one facility in the 2016 DMR, potentially related to CTA manufacturing (SIC
code 3861 - Photographic Equipment and Supplies) that reported water releases. Release for this
facility is summarized in Table 2-8. EPA did not identify any potential CTA manufacturing
facilities in the 2016 TRI that reported water releases. For the site reporting for this scenario, the
release estimate is 29 kg/site-yr over 250 days/yr.
Table 2-8. Reported 2016 TRI and DMR Releases for CTA Manufacturing Facilities
Silo Idinlilv
< i(\
si shi-
Annusil
Ki-k-sisi-
(kii/sili'-\ n
Annusil
Ki-k-sisi- l)si\s
(dsi\s/\ r)
l)siil\ Ki-k-sisi-
(k*i/sik--(lsi\)
Kok-siso
Mi-riisi
Sources K:
Noles
KODAK
PARK
DIVISION
ROCHESTER
ny
29
250
0.1
Surface
Water
EPA (20.1.6)
2.2.2.15 Flexible Polyurethane Foam Manufacturing
EPA assumed that sites classified under NAICS code 326150 (Urethane and Other Foam Product
(except Polystyrene) Manufacturing) are potentially applicable to polyurethane foam
manufacturing.
Table 2-9 lists one facility under this NAICS code that reported direct or indirect water releases
in the 2016 TRI. EPA did not identify water releases for polyurethane manufacturing sites in the
2016 DMR. This facility (Previs Innovative Packaging, Inc. in Wurtland, KY) reported 2
kilograms release to surface water (	317f), and EPA estimates 250 days/yr release.
Other facilities in this industry may not dispose to water or use methylene chloride in quantities
that meet the TRI reporting threshold.
Page 86 of 753

-------
Table 2-9. Water Releases Reported in 2016 TRI for Polyurethane Foam Manufacturing
Sill- l(k-nlil\
< ii\
Slsili-
Annii.il
Ri'k*;isi-
(k/siii--\ r)
A n nihil
Ri-k-;isi- l):i\s
(il;i\s/\ r)
l);iil\
Ri'k'iisi*
(k/sik--
d;i\)
RlllilSl"
\k'di;i
Suurivs
Niik-s
PREGIS
INNOVATIVE
PACKAGING INC
WURTLAND
KY
2
250
0.01
Surface
Water
U.S. EPA
For chemical industries (including blowing agent in PUR production, which is applicable to this
OES), calculations for the Dutch chemical industry estimated emissions of 0.2 % to water, 64.8
% to air and 35 % to waste, based on a mass balance study (T>	>99).
2.2,2.16 Laboratory Use
EPA did not identify quantitative information about potential water releases during laboratory
use of methylene chloride. The majority of methylene chloride is expected to evaporate into the
air or disposed as hazardous waste, but releases to water may occur if equipment is cleaned with
water.
2.2.2.17 Plastic Product Manufacturing
EPA identified facilities classified under four NAICS and SIC codes, listed in Table 2-10, that
reported water releases in the 2016 TRI and 2016 DMR and may be related to plastic product
manufacturing. Table 2-11 lists all facilities classified under these NAICS and SIC codes that
reported direct or indirect water releases in the 2016 TRI or 2016 DMR. For the sites reporting
for this scenario, the release estimates range from 0.02 to 28 kg/site-yr over 250 days/yr.
Table 2-10. Potential Industries Conducting Plastics Product Manufacturing in 2016 TRI
or DMR
NAICS Cotlc
NAICS Description
325211
Plastics Material and Resin Manufacturing
2821
PLSTC MAT./SYN RESINS/NV ELAST
2822
SYN RUBBER (VULCAN ELASTOMERS)
3081
UNSUPPORTED PLSTICS FILM/SHEET
Table 2-11. Reported 2016 TRI and DMR Releases for Potential Plastics Product
Manufacturing Facilities 					
Silc l(kii(i(\
Cilj
Slsili*
Amiiiiil
Ki'li'.isi*
(kji/siU'-j n
Aniuiiil
Ki'li'.isi* Dsijs
()
Ki'li'.isi*
Modiii
Sources
Nolcs
SABIC
INNOVATIVE
PLASTICS US
LLC
BURKVILLE
AL
8
250
0.03
Surface
Water
U.S. EPA
(2017:f)
SABIC
INNOVATIVE
MOUNT
VERNON
IN
28
250
0.1
Surface
Water
EPA (2016)

Page 87 of 753

-------
Silo Idculilt
Cilj
S(;i(c
Anniiiil
Uclc.isc
ikg/siic-> n
Anniiiil
Kclc.isc Dsijs
(d;i\s/> r)
l);iih Kclc;isc
(k;i/si(c-(l;i\)
Release
Medi;i
Sources Si
No les
PLASTICS MT.
VERNON, LLC







SABIC
INNOVATIVE
PLASTICS US
LLC
SELKIRK
NY
9
250
0.03
Surface
Water
EPA (2016)

EQUISTAR
CHEMICALS LP
LA PORTE
TX
9
250
0.03
Surface
Water
EPA (2016)

CHEMOURS
COMPANY FC
LLC
WASHINGTON
WV
7
250
0.03
Surface
Water
EPA (2016)

SHINTECH
ADDIS PLANT
A
ADDIS
LA
3
250
0.01
Surface
Water

STYROLUTION
AMERICA LLC
CHANNAHON
IL
0.2
250
0.001
Surface
Water
EPA (20.1.6)
DOW
CHEMICAL CO
DALTON
PLANT
DALTON
GA
0.3
250
0.001
Surface
Water

PREGIS
INNOVATIVE
PACKAGING
INC
WURTLAND
KY
0.02
250
0.0001
Surface
Water
EPA (20.1.6)
2,2,2.18 Lithographic Printing Plate Cleaning
EPA identified one facility in the 2016 DMR, potentially related to lithographic printing (SIC
code 2752 - Commercial Printing, Lithographic) that reported water releases. Release for this
facility is summarized in Table 2-12. EPA did not identify any potential lithographic printing
facilities in the 2016 TRI that reported water releases. Other facilities in this industry may not
dispose to water or use methylene chloride in quantities that meet the TRI reporting threshold.
For the site reporting for this scenario, the release estimate is 0.001 kg/site-yr over 250 days/yr.
Table 2-12. Reported 2016 TRI and DMR Releases for Potential Lithographic Printing
Facilities
Silc llciilil>
Cilj
Sliilc
Anniiiil
Release
(kii/silc-
> r)
Anniiiil
Release
l)a j s
(da\s/> n
l)ail\
Release
(kii/silc-
d:i>)
Kclciisc
Mcdiii
Sources Si Nolcs
FORMER
REXON
FACILITY
AKA ENJEMS
MILLWORKS
WAYNE
TWP
NJ
0.001
250
0.000004
Surface
Water
EPA (20.1.6)
Page 88 of 753

-------
2.2.2.19	Non-Aerosol Commercial Uses
EPA did not identify quantitative information about potential water releases during non-aerosol
use of methylene chloride. The majority of methylene chloride is expected to evaporate into the
air, but releases to water may occur if equipment is cleaned with water.
2.2.2.20	Waste Handling, Disposal, Treatment, and Recycling
EPA identified facilities classified under five NAICS and SIC codes, listed in Table 2-13, that
reported water releases in the 2016 TRI and 2016 DMR and may be related to recycling/disposal.
Table 2-14 lists all facilities classified under these NAICS and SIC codes that reported direct or
indirect water releases in the 2016 TRI or 2016 DMR. To estimate the daily release, EPA used a
default assumption of 250 days/yr of operation and averaged the annual release over the
operating days. For the sites reporting for this scenario, the release estimates range from 0.02 to
115,059 kg/site-yr over 250 days/yr.
Table 2-13. Potential Industries Conducting Waste Handling, Disposal, Treatment, and
Recycling in 2016 TRI or DMR	
NAKS/SK
Code
NAICS/SIC Description
331492
Secondary Smelting, Refining, and Alloying of Nonferrous Metal (except
Copper and Aluminum)
562211
Hazardous Waste Treatment and Disposal
4953
REFUSE SYSTEMS
7699
REPAIR SHOPS & RELATED SERVICE
9511
AIR & WATER RES & SOL WSTE MGT
Table 2-14. Reported 2016 TRI and DMR Releases for Potential Recycling/Disposal
Facilities
Silo l(k'iilil>
Cilj
Slsili-
Amiiiiil
Koloiiso
(kii/sik'-\ n
Amiiiiil
Kok'iiso Dsijs
(dii>s/> i-)
l);iil\
Kck'iiso
(k*i/si(e-
(l;i> )
Ki'k'sisi*
Mi'rifci
Sources
Noll's
JOHNSON
MATTHEY
WEST DEPTFORD
NJ
620
250
2
Non-
POTW
WWT
U.S. EPA
(2017f)
CLEAN
HARBORS DEER
PARK LLC
LA PORTE
TX
522
250
2
Non-
POTW
WWT
U.S. EPA
(2017f)
CLEAN
HARBORS EL
DORADO LLC
EL DORADO
AR
113
250
0.5
Non-
POTW
WWT
U.S. EPA
(2017f)
TRADEBE
TREATMENT &
RECYCLING LLC
EAST CHICAGO
IN
19
250
0.1
Non-
POTW
WWT
U.S. EPA
(2017f)
Page 89 of 753

-------
Silo ldculil\
< il\
Sliilo
Amiiiiil
Rele;ise
(kii/sik'-\ r)
Amiiiiil
Rele;ise l);i\s
l);iil\
Rcle;ise
(kji/silc-
(l;i\)
Uclc.isc
Modiii
Sources Si
Noles
VEOLIA ES
TECHNICAL
SOLUTIONS LLC
WEST
CARROLLTON
OH
2
250
0.01
POTW
U.S. EPA
(2017:0
VEOLIA ES
TECHNICAL
SOLUTIONS LLC
AZUSA
CA
0.5
250
0.002
POTW
U.S. EPA
(2017:0
VEOLIA ES
TECHNICAL
SOLUTIONS LLC
MIDDLESEX
NJ
115,059
250
460
99.996%
Non-
POTW
WWT
0.004%
POTW
U.S. EPA
2017|}
CHEMICAL
WASTE
MANAGEMENT
EMELLE
AL
4
250
0.01
Surface
Water
EPA (2016)
OILTANKING
HOUSTON INC
HOUSTON
TX
1
250
0.003
Surface
Water
EPA (2016)
HOWARD CO
ALFA RIDGE
LANDFILL
MARRIOTTSVILLE
MD
0.1
250
0.0002
Surface
Water
EPA (2016)
CLIFFORD G
HIGGINS
DISPOSAL
SERVICE INC SLF
KINGSTON
NJ
0.02
250
0.0001
Surface
Water
EPA (2016)
CLEAN WATER
OF NEW YORK
INC
STATEN ISLAND
NY
2
250
0.01
Surface
Water
EPA (2016)
FORMER
CARBORUNDUM
COMPLEX
SANBORN
NY
0.2
250
0.001
Surface
Water
EPA (2016)
2.2,2.21 Other Unclassified Facilities
Table 2-15 summarizes TRI and DMR releases for facilities that were unable to be classified in
one of the assessed scenarios. For the sites reporting for unclassified scenarios, the release
estimates range from 0.0002 to 42 kg/site-yr over 250 days/yr.
Table 2-15. Reported 2016 TRT and DMR Releases for Other Unclassified Facilities
Silo Idculilt
Cilj
Sliilo
Anniiiil
Relc;ise
(ki;/sile-\ n
AiiiiiisiI
Rcle;isc l);i\s
(d;i\s/> r)
l)
Uck'iiso
(kii/sile-
d)
Kok'iiso
Mi-diii
Sources Si
Nolcs
APPLIED
BIOSYSTEMS
LLC
PLEASANTON
CA
42
250
0.2
Non-
POTW
WWT
U.S. EPA
(2017f)
Page 90 of 753

-------
Silo 1 (kill it \
( il\
Slsile
Anniiiil
Rclc;isc
(kii/sik'-\ n
Aiiiiii;iI
Rclc;isc D.ijs
(d;i\s/\ r)
l)
Uck'iisc
(kg/silc-
(l;i\)
Rcle;isc
Modhi
Sources Si
Nulcs
EMD
MILLIPORE
CORP
JAFFREY
NH
2
250
0.01
POTW
U.S. EPA
(2017:f)
GBC METALS
LLC SOMERS
THIN STRIP
WATERBURY
CT
0.2
250
0.001
Surface
Water
EPA (2016)
HYSTER-
YALE GROUP,
INC
SULLIGENT
AL
0.0002
250
0.000001
Surface
Water
EPA (2016)
AVNET INC
(FORMER
IMPERIAL
SCHRADE)
ELLENVILLE
NY
0.005
250
0.00002
Surface
Water
EPA (2016)
BARGE
CLEANING
AND REPAIR
CHANNEL VIEW
TX
0.1
250
0.0003
Surface
Water
EPA (2016)
AC & S INC
NITRO
WV
0.01
250
0.00005
Surface
Water
EPA (2016)
MOOG INC -
MOOGIN-
SPACE
PROPULSION
ISP
NIAGARA FALLS
NY
0.003
250
0.00001
Surface
Water
EPA (2016)
OILTANKING
JOLIET
CHANNAHON
IL
1
250
0.003
Surface
Water
EPA (2016)
NIPPON
DYNAWAVE
PACKAGING
COMPANY
LONG VIEW
WA
22
250
0.1
Surface
Water
EPA (2016)
TREE TOP INC
WENATCHEE
PLANT
WENATCHEE
WA
0.01
250
0.00003
Surface
Water
EPA (2016)
CAROUSEL
CENTER
SYRACUSE
NY
0.001
250
0.000002
Surface
Water
EPA (2016)
2.2.3 Summary of Water Release Assessment
EPA found that most of the facilities reporting water releases to TRI and DMR could be
classified into scenarios associated with conditions of use of methylene chloride. Magnitudes of
releases of methylene chloride to water can vary highly (e.g., orders of magnitude) within most
scenarios, ranging from 0.0002 to 115,059 kg/site-yr, likely due to site-specific processes and
handling of methylene chloride. Some of the largest releases reported are associated with the
Waste Handling, Disposal, Treatment, and Recycling; and Processing - incorporation into
formulation, mixture, or reaction product scenarios. Data or information and methods needed to
estimate releases were not found for Adhesives and Sealants, Paints and Coatings, Aerosol
Degreasing/ Lubricants, Batch Open-Top Vapor Degreasing, Conveyorized Vapor Degreasing,
Page 91 of 753

-------
Cold Cleaning, Adhesive and Caulk Removers, Fabric Finishing, Laboratory Use, Non-Aerosol
Industrial and Commercial Use scenarios. While some sites in some of these scenarios without
quantitative water release estimates may have water releases, it is reasonable to assume that such
water releases would be less than most releases reported to TRI and DMR, which are expected to
have the highest volumes and releases of methylene chloride. A table of facilities for all
scenarios is in Appendix E. Uncertainties are discussed in Key Assumptions and Uncertainties in
the Environmental Exposure Assessment Section 4.4.1.
2.3 Environmental Exposures
2.3.1 Environmental Exposures Approach and Methodology
The environmental exposure characterization focuses on aquatic releases of methylene chloride
from facilities that use, manufacture, or process methylene chloride under industrial and/or
commercial conditions of use. To characterize environmental exposure, EPA assessed point
estimate exposures derived from both measured and predicted concentrations of methylene
chloride in surface water in the U.S. Measured surface water concentrations were obtained from
EPA's Water Quality Exchange (WQX) using the Water Quality Portal (WQP) tool, which is the
nation's largest source of water quality monitoring data and includes results from EPA's
STOrage and RETrieval (STORET) Data Warehouse, the United States Geological Service
(USGS) National Water Information System (NWIS), and other federal, state, and tribal sources.
A literature search was also conducted to identify other peer-reviewed or grey literature10 sources
of measured surface water concentrations in the U.S., however, no data were found after 2000.
Predicted surface water concentrations were modeled for facility releases as detailed in Section
2.2 for reporting year 2016, as determined from EPA's TRI and from DMR; through EPA's
Water Pollutant Loading Tool). The aquatic modeling was conducted with EPA's Exposure and
Fate Assessment Screening Tool, version 2014 (E-FAST 2014) (EPA. 2007). using reported
annual release/loading amounts (kg/yr) and estimates of the number of days/yr that the annual
load is released (see Section 2.2 for more information). As appropriate, two scenarios were
modeled per release: release of the annual load over an estimated maximum number of operating
days/yr and over only 20 days/yr. Twenty days of release was modeled as the low-end release
frequency at which possible ecologic risk from chronic exposure could be determined. The 20-
day risk from chronic exposure criterion is derived from partial life cycle tests (e.g., daphnid
chronic and fish early life stage tests) that typically range from 21 to 28 days in duration.
Additionally, the Probabilistic Dilution Model (PDM), a module of E-FAST 2014 was run to
predict the number of days a stream concentration will exceed the designated concentration of
concern (COC) value. The measured concentrations reflect localized ambient exposures at the
monitoring sites, and the modeled concentrations reflect near-site estimates at the point of
release. A geospatial analysis at the subbasin and subwatershed level (Hydrologic Unit Code
(HUC)-8 and HUC-12 level respectively) was conducted to compare the measured and predicted
surface water concentrations from known facility releases and investigate if the facility releases
10 Gray literature refers to sources of scientific information that are not formally published and distributed in peer
reviewed journal articles. These references are still valuable and consulted in the TSCA risk evaluation process.
Examples of grey literature are theses and dissertations, technical reports, guideline studies, conference proceedings,
publicly-available industry reports, unpublished industry data, trade association resources, and government reports.
(ENREF 3881
Page 92 of 753

-------
may be associated with the observed concentrations in surface water. Hydrologic Unit Codes are
a geographically hierarchical tiered approach to organizing stream networks across the United
States from regions to subwatersheds and part of the Watershed Boundary Dataset developed by
U.S. Geological Survey and U.S. Department of Agriculture (USGS. , ). HUC-8 and HUC-12
sized units were selected as relevant sized units as they were expected to give a representative
geographic size range over which potentially collocated predicted SWCs from known facility
releases and measured SWCs would be spatially relevant.
2.3.1.1 Methodology for Obtaining Measured Surface Water Concentrations
To characterize environmental exposure in ambient water for methylene chloride, EPA used two
approaches to obtain measured surface water concentrations. One approach was to pull
monitoring data on surface water concentrations from the WQP, and the second was to conduct a
systematic review of surface water concentrations in peer reviewed and gray literature.
The primary source of ambient surface water monitoring data was the WQP, which integrates
publicly available U.S. water quality data from multiple databases: 1) USGS NWIS, 2)
STORET, and 3) the USDA ARS Sustaining The Earth's Watersheds - Agricultural Research
Database System (STEWARDS). For methylene chloride, the data retrieved originated from the
NWIS and STORET databases. NWIS is the Nation's principal repository of water resources data
USGS collects from over 1.5 million sites, including sites from the National Water-Quality
Assessment (NAWQA). STORET refers to an electronic data system originally created by EPA
in the 1960's to compile water quality monitoring data. NWIS and STORET now use common
web services, allowing data to be published through WQP tool. The WQP tool and User Guide is
accessed from the following website: ("http://www.waterqualitvdata.us/portal.ispy
Surface water data for methylene chloride were downloaded from the WQP on October 3, 2018.
The WQP can be searched through three different search options: Location Parameters, Site
Parameters, and Sampling Parameters. The methylene chloride data were queried through the
Sampling Parameters search using the Characteristics parameter (selected "Methylene Chloride
(NWIS, STORET)") and Date Range parameter (selected "01-01-2013 to 12-31-2017"). Both the
"Site data only" and "Sample results (physical/chemical metadata)" were selected for download
in "MS Excel 2007+" format. The "Site data only" file contains monitoring site information (i.e.,
location in hydrologic cycle, HUC and geographic coordinates); whereas the "Sample result" file
contains the sample collection data and analytical results for individual samples.
The "Site data only" and "Sample results (physical/chemical metadata)" files were linked
together using the common field "Monitoring Location Identifier" and then filtered and cleansed
to obtain surface water samples for years 2013 through 2017. Specifically, cleansing focused on
obtaining samples that were only for the media of interest (i.e., surface water), were not quality
control (QC) samples (i.e., field blanks), were of high analytical quality (i.e., no QC issues,
sample contamination, or estimated values), and were not associated with contaminated sites
(i.e., Superfund).
Following filtering to obtain the final dataset, additional domains were examined to identify
samples with non-detect concentrations. All non-detect samples were tagged and the
concentrations were converted to V2 the reported detection limit for summary calculation
Page 93 of 753

-------
purposes. If a detection limit was not provided, calculations were performed using the average of
the reported detection limits in all samples (calculated as 1.46 |ig/L).
In addition to using data from WQP, EPA conducted a full systematic review of published
literature to identify studies reporting concentrations of methylene chloride in surface water
associated with background levels of contamination or potential releases from facilities that
manufacture, process, use and/or dispose of methylene chloride in the U.S. Studies clearly
associated with releases from Superfund sites, improper disposal methods, and landfills were
considered out of scope due to being regulated under other environmental statutes administered
by EPA and excluded from data evaluation and extraction. The systematic review process is
described in detail in Section 1.5. A total of seven surface water studies were extracted and the
results are summarized in Section 2.3.2.1. No concentration data from the U.S. was identified
prior to 2000.
2,3,1.2 Methodology for Modeling Surface Water Concentrations from Facility Releases
(E-FAST 2014)
Surface water concentrations resulting from wastewater releases of methylene chloride from
facilities that use, manufacture, or process methylene chloride were modeled using EPA's E-
FAST, Version 2014 (I P \ .10071 E-FAST 2014 is a model that estimates chemical
concentrations in water to which aquatic life may be exposed using upper percentile and/or mean
exposure parametric values, resulting in possible conservative exposure estimates. Other
assumptions and uncertainties in the model, including ways it may be underestimating or
overestimating exposure, are discussed in the Sections 4.4.1 and 4.4.6. Advantages to this model
are that it requires minimal input parameters and it has undergone extensive peer review by
experts outside of EPA. A brief description of the calculations performed within the tool, as well
as a description of required inputs and the methodology to obtaining and using inputs specific to
this assessment is described in Section 2.3.2.1. To obtain more detailed information on the E-
FAST 2014 tool from the user guide/background document, visit this web address:
https://www.epa.gov/tsca-screening-tools/e-fast-exposure-and-fate-assessment-screening-tool-
version-2014/. All model runs for this assessment were conducted between December 2018 and
June 2019.
In some ways the E-FAST estimates are underestimating exposure, because data used in E-FAST
include TRI and DMR data, and TRI does not include smaller facilities with fewer than 10 full
time employees, nor does it cover certain sectors, such as dry cleaners, or oil and gas extraction.
In some ways the E-FAST estimates are overestimating exposure, because methylene chloride is
a volatile chemical, but E-FAST doesn't take volatilization into consideration; and, for static
water bodies, E-FAST doesn't take dilution into consideration.
2.3.1.2.1 E-FAST Calculations
Surface Water Concentrations
EPA used E-FAST 2014 to estimate site-specific surface water concentrations for discharges to
both free-flowing water bodies (i.e., rivers and streams) and for still water bodies (i.e., bays,
lakes, and estuaries).
Page 94 of 753

-------
For free-flowing water body assessments, E-FAST 2014 calculates surface water concentrations
for four streamflow conditions (7Q10, harmonic mean, 30Q5, and 1Q10 flows) using the
following equation:
where:
swc
WWR
WWT
SF
CF1
CF2
SWC =
WWR xCF1 x 1
WWT\
SF xCF2
(Eq. 2-1)
Surface water concentration (parts per billion (ppb) or |ig/L)
Chemical release to wastewater (kg/day)
Removal from wastewater treatment (%)
Estimated flow of the receiving stream (million liters/day (MLD))
Conversion factor (109 |ig/kg)
Conversion factor (106 L/day/MLD)
For still water body assessments, no simple streamflow value represents dilution in these types of
water bodies. As such, E-FAST 2014 accounts for dilution by incorporating an acute or chronic
dilution factor for the water body of interest instead of stream flows. Dilution factors in E-FAST
2014 are typically 1 (representing no dilution) to 200, based on NPDES permits or regulatory
policy. The following equation is used to calculate surface water concentrations in still water
bodies:
SWC =
( WWT\
WWRx(l--^-)xCFl
	V 100 J	
PFXCF2XDF
(Eq. 2-2)
where:
SWC
WWR
WWT
PF
DF
CF1
CF2
(typically
Surface water concentration (ppb or |ig/L)
Chemical release to wastewater (kg/day)
Removal from wastewater treatment (%)
Effluent flow of the discharging facility (MLD)
Acute or chronic dilution factor (DF) used for the water body
between 1 and 200)
Conversion factor (109 |ig/kg)
Conversion factor (106 L/day/MLD)
Outputs
There are two main outputs from E-FAST that EPA used in characterizing environmental exposures:
surface water concentration estimates, and the number of days a certain surface water concentration
was exceeded. Site-specific surface water concentration estimates for free-flowing water bodies are
reported for the 7Q10 stream flows. The 7Q10 stream flow is the lowest consecutive 7-day average
flow during any 10-year period. Site-specific surface water concentration estimates for still water
bodies are reported for calculations using the acute dilution factors. In cases where site-specific
flow/dilution data were not available, the releases were modeled using stream flows of a
representative industry sector, as calculated from all facilities assigned to the industry sector in
the E-FAST database (discussed below). Estimates from this calculation method are reported for the
10th percentile 7Q10 stream flows.
Page 95 of 753

-------
The PDM portion of E-FAST 2014 was also run for free-flowing water bodies. The PDM
predicts the number of days/yr a chemical's COC in an ambient water body will be exceeded.
COCs are threshold concentrations below which adverse effects on aquatic life are expected to
be minimal. The model is based on a simple mass balance approach presented by (Pi Toro.
1984) that uses probability distributions as inputs to reflect that streams follow a highly variable
seasonal flow pattern and there are numerous variables in a manufacturing process that can affect
the chemical concentration and flow rate of the effluent. PDM does not estimate exceedances for
chemicals discharged to still waters, such as lakes, bays, or estuaries. For these water bodies, the
days of exceedance is assumed to be zero unless the predicted surface water concentration
exceeds the COC. In these cases, the days of exceedance is set to the number of release days/yr
(see required inputs in 2.3.1.2.2).
2.3.1.2.2 Model Inputs
Individual model inputs and accompanying considerations for the surface water modeling are described
in this section.
Chemical Release to Wastewater (WWR)
Annual wastewater loading estimates (kg/site/year or lb/site/year) were obtained from 2016 TRI and
2016 DMR, as discussed in Section 2.2. To model these releases within E-FAST 2014, the annual
release is converted to a daily release using an estimated days of release per year. Below is an example
calculation:
WWR (kg/day) = Annual loading (kg/site/year) * Days released per year (days/year) (Eq. 2-3)
In cases where the total annual release amount from one facility was discharged via multiple
mechanisms (i.e., direct to surface water and/or indirectly through one or more WWTPs), the annual
release amount was divided accordingly based on reported information in TRI (Form R).
Release Days (days/yr)
The number of days/yr that the chemical is discharged is used to calculate a daily release amount from
annual loading estimates (see above). Current regulations do not require facilities to report the number
of days associated with reported releases. Therefore, two release scenarios were modeled for direct
discharging facilities to provide upper and lower bounds for the range of surface water concentrations
predicted by E-FAST 2014. The two scenarios modeled are a maximum release frequency (250 to 365
days) based on estimates specific to the facility's condition of use (see Section 2.2.1 for more details)
and a low-end release frequency of 20 days of release per year as an estimate of releases that could lead
to risk from chronic exposure. The 20-day risk from chronic exposure criterion is derived from
partial life cycle tests (e.g., daphnid chronic and fish early life stage tests) that typically range
from 21 to 28 days in duration. For indirect dischargers, only the maximum estimated days of release
per year was modeled because it was assumed that the actual release to surface water would mostly
occur at receiving treatment facilities, which were assumed to typically operate greater than 20 days/yr.
Removal from Wastewater Treatment (WWT%)
The WWT% is the percentage of the chemical removed from wastewater during treatment before
discharge to a body of water. As discussed in Section 2.1, the WWT% for methylene chloride
was estimated as 57% using the "STP" module within EPI Suite, which was run using default
Page 96 of 753

-------
settings to evaluate the potential for methylene chloride to volatilize to air or sorb to sludge
during wastewater treatment. The WWT% of 54% was applied to releases from indirect
discharging facilities because the releases are transferred off-site for treatment at a WWTP prior
to discharge to surface water. A WWT% of zero was used for direct releasing facilities because
the release reported in TRI and DMR already accounts for any wastewater treatment which may
have occurred.
Facility or Industry Sector
The required site-specific stream flow or dilution factor information for a given facility is
contained in the E-FAST 2014 database and is selected by searching by a facility's NPDES permit
number, name, or the known discharging waterbody reach code. For facilities that directly discharge to
surface water (i.e., "direct dischargers"), the NPDES code of the direct discharger was selected from the
database. For facilities that indirectly discharge to surface water (i.e., "indirect dischargers" because the
release is sent to a WWTP prior to discharge to surface water), the NPDES of the receiving WWTP was
selected. The receiving facility name and location was obtained from the TRI database (Form R), if
available. As TRI does not contain the NPDES code of receiving facilities, the NPDES was obtained
using EPA's EnviroFacts search tool (https://www3.epa.gov/enviro/facts/multisvstem.html). If a facility
NPDES was not available in the E-FAST-2014 database, the release was modeled using water body data
for a surrogate NPDES code (preferred) or an industry sector, as described below.
Surrogate NPDES: In cases where the site-specific NPDES code was not available in the
E-FAST 2014 database, the preferred alternative was to select the NPDES for a nearby facility
that discharges to the same waterbody. The surrogate NPDES was chosen to best represent flow
conditions in the waterbody that both the methylene chloride releasing facility and surrogate
facility discharge to and not actual releases associated with the surrogate facility NPDES.
Industry Sector (SIC Code Option): If the NPDES code is unknown, no close analog could
be identified, or the exact location of a chemical loading is unknown, surface water
concentrations were modeled using the "SIC Code Option" within E-FAST 2014. This option
uses the 10th and 50th percentile receiving 7Q10 stream flows for dischargers in a given industry
sector, as defined by the SIC codes of the industry. The industrial activity associated with the
SIC or alternatively the NAICS of the facility in question was examined to select the most
representative industry sector for modeling in E-FAST 2014.
2.3.1.3 Methodology for Geospatial Analysis of Measured Surface Water Monitoring and
Modeled Facility Releases
Using 2016 data, the measured surface water concentrations from the WQP and predicted
concentrations from the modeled facility releases were mapped in ArcGIS Version 10.6 to
conduct a watershed analysis at the HUC-8 and HUC-12 level (these results are shown in Section
2.3.2.3 in Figure 2-6 through Figure 2-8). The purpose of the analysis was to identify if any of
the observed surface water concentrations could be attributable to the modeled facility releases.
In addition, the analysis included a search for Superfund sites within 1 to 5 miles of the surface
water monitoring stations.
The locations of the monitoring stations were determined from the geographic coordinates
(latitude and longitude) provided in WQP. Location of releases from facilities were located based
Page 97 of 753

-------
on the geographic coordinates for the NPDES, TRI, and/or Facility Registry Service
Identification (FRS ID) of the mapped facility, as provided by FRS. For indirect dischargers, the
location of the receiving facility was mapped if known. If the receiving facility was not known,
the location of the indirect discharger was mapped. Superfund sites in 2016 were identified and
mapped using geographic coordinates as reported in the Superfund Enterprise Management
System (SEMS) database in EnviroFacts (https://www.epa.gov/enviro/sem.s-search).
A U.S. scale map was developed to provide a spatial representation of the measured
concentrations from monitoring and predicted instream concentrations from discharging facilities
(Section_2.3.2.3). HUC-8s or HUC-12s with co-located monitoring stations and facility releases
were identified and examined further through development of localized maps at the HUC scale.
2.3.2 Environmental Exposure Results
2.3.2.1 Measured Surface Water Concentrations
Measured Surface Water Concentrations from WQX/WQP
The original dataset downloaded contained 29,084 entries for sample years 2013 through 2017.
Following the filtering and cleansing procedure, only 8% of the samples remained (n = 2,286 for
2013-2017). The majority of the samples were removed because they were an off-topic media
(i.e., groundwater, artificial, bulk deposition, leachate, municipal waste, or stormwater) or
location type (i.e., landfill, seep, spring, or well). Those media and locations deemed off-topic
are discussed more fully in Section 1 and (	c). Of the surface water samples that
were removed, -99% were QC samples (field or laboratory blanks, spikes, or replicates). Other
samples were removed because of monitoring conducted at a Superfund site (i.e., Palermo
Wellfield Superfund Site) or QC issues.
For the 2016 final dataset (n = 471 samples), observations were made in 10 states (AZ, KS, MN,
MO, NJ, NM, NC, PA, TN, TX) at 109 unique monitoring sites, with 1 to 47 samples collected
per site. On a watershed level, observations were made in 44 HUC-8 areas and 98 HUC-12 areas.
The majority of HUCs had only one monitoring site (55% for HUC-8; 93% for HUC-12). Up to
12 sites were present in an HUC-8 and up to 4 sites in an HUC-12. A list of individual HUCs,
including the number of monitoring sites and samples in each HUC, is provided in TableApx
E-l for HUC-8 and Table Apx E-2 for HUC-12. For geospatial representation of these measured
samples see Figure 2-2 to Figure 2-5.
A summary of the WQX data obtained from the WQP is provided in Table 2-16 below for years
2013-2017. Per year, the final evaluated datasets contained between 52 and 797 surface water
samples collected from 28 to 116 unique monitoring stations. Detection frequencies were low,
ranging from 1.1 to 5.1%. Concentrations ranged from not detected (ND; <0.04-10) to 2.5 |ig/L
in 2013, ND (<0.04-5) to 1.2 |ig/L in 2014, ND (<0.04-4) to 0.5 |ig/L in 2015, ND (<0.04-5) to
29 |ig/L in 2016, and ND (<0.04-5) to 0.61 |ig/L in 2017. Non detect values are reported as a
range because of differences in reported detection limits in measured samples due to likely
differences in sampling routine, methodology, and precision in available analysis tools. The
highest measured value was observed in 2016; however, caution should be used in interpreting
Page 98 of 753

-------
trends with this data due to the small number of samples and the lack of samples collected from
the same sites over multiple years.
Table 2-16. Measured Concentrations of Methylene Chloride in Surface Water Obtained
from the Water Quality Portal (WQP): 2013-2017"	
Ywir
Dclci'lion
l"lV(|IIOIIO
( oihtiiIi';i
No. of S;iiii|)k's
(No. of I ni(|iie
Millions)
lion in All S;impk
Riiniic
'S (llli/l.)
A\er;iiie 
Sliindiird
l)c\ iiilion
(SI))*
( oniTiilr;ilioi
\bo\c |
No. orSiiniplcs
(No. of I ni(|iio
Sliilions)
s (iiii/l.) in (
lie Doloclioi
Uiiniic
)nl> Siimpk's
l.iniil
A\er;ijie  SI)
C
2013
5.1%
797 (166)
ND (<0.04-10)
to 2.5
1.38 2.0
41 (26)
0.5 to 2.5
0.57 0.33
2014
1.8%
611 (157)
ND (<0.04-5) to
1.2
0.34 0.32
11(11)
0.13 to 1.2
0.53 0.29
2015
1.1%
355 (94)
ND (<0.04-4) to
0.5
0.43 0.21
4(2)
0.04 to
0.07
0.05  0.02
2016
1.1%
471 (109)
ND (<0.04-5) to
29
0.61  1.9
5(3)
1.2 to 29
13.1  14.6
2017
1.9%
52 (28)
ND (<0.04-5) to
0.61
0.59  1.0
1(1)
0.61
0.61
All 5
Years
2.7%
2,286 (389)
ND (<0.04-10)
to 29
0.78  1.5
62 (42)
0.04 to 29
1.54 5.10
a.	Data were downloaded from the WQP (www.watergnalitvdata.us') on 10/3/2018. NWIS and STORET surface
water data were obtained by selecting "Methylene chloride (NWIS, STORET)" for the Characteristic and
selecting for surface water media and locations only. Results were reviewed and filtered to obtain a cleansed
dataset (i.e., samples/sites were eliminated if identified as estimated, QC, media type other than surface water,
Superfund, landfill, failed laboratory QC, etc.).
b.	ND = Not Detected. Reported detection limits in all samples ranged from 0.04 to 10 |ig/L.
c.	Calculations were performed using '/? the reported detection limit when results were reported as not detected. If a
detection limit was not provided, calculations were performed using the average of the reported detection limits
in all samples (1.46 |ig/L).
The quantitative environmental assessment used the 2016 data set only to allow direct
comparison with known TRI and DMR releasers from the same year. For the 2016 data, only 5
samples from 3 monitoring sites (all in North Carolina) had methylene chloride concentrations
above the detection limit, as shown in Table 2-17. The average of these samples was 13.1 |ig/L.
It should be noted that two of the sites (Clinton, NC and Mills River, NC) each had two samples
collected on the same day within 5-15 minutes (min) of each other. Both samples had identical
measured concentrations: 1.2 |ig/L in Clinton, NC and 29 |ig/L in Mills River, NC. The last site
(Ashville, NC) had a concentration of 5 |ig/L in one sample. No samples were collected at these
three sites in other years between 2013 and 2017.
A detailed summary of results for all samples collected between 2013 and 2017 with
concentrations above the detection limit is provided in Table Apx E-3.
Page 99 of 753

-------
Table 2-17. Sample Information for Water Quality Exchange (WQX) Surface Water
Observations With Concentrations Above the Reported Detection Limit: Year 2016a
Monitor
Monitoring Silo II)
iiml Oi'^iini/iilion
inji Silo In lorn
Wsilcrhmlt
l \|H' iind
Locution
iilion
l.ill/I.OIIli
III ( X
S:ini|
S;i in pie II)
lc Inloi'iiiiilio
Diilo iind
Time
n
( oneonli'iilion
(HSi/l.)1'
21NC03 WQ-B8484000
North Carolina
Department of
Environmental
Resources NCDENR
-DWQ WQX
River/Stream
BEARSKIN
SWAMP AT
SR 1325 NR
Clinton, NC
35.08754/
-78.43463
3030006
21NC03WQ-
AMS20161206-
B8484000-
370870277
2016-12-06
11:40:00
EST
1.2
21NC03WQ-
AMS20161206-
B8484000-
381057619
2016-12-06
11:55:00
EST
1.2
21NC03WQ-E1485000
North Carolina
Department of
Environmental
Resources NCDENR
-DWQ WQX
River/Stream
North Mills
River at SR
1343 (River
Loop Rd) nr
Mills River,
NC
35.39412/
-82.61646
6010105
21NC03WQ-
AMS20160822-
E1485000-
381059366
2016-08-22
15:55:00
EST
29
21NC03WQ-
AMS20160822
-E1485000-
381059612
2016-08-22
16:00:00
EST
29
21NC03WQ-E3475000
North Carolina
Department of
Environmental
Resources NCDENR
-DWQ WQX
River/Stream
Hominy
Creek at Pond
Rd in
Asheville,
NC
35.54683/
-82.60264
6010105
21NC03WQ-
RAMS20160817-
E3475000-
370533933
2016-08-17
17:05:00
EST
5
a. Data were downloaded from the WQP (www.waterqualitvdata.ns') on 10/3/2018. NWIS and STORET surface
water data were obtained by selecting "Methylene chloride (NWIS, STORET)" for the Characteristic and
selecting for surface water media and locations only. Results were reviewed and filtered to obtain a cleansed
dataset (i.e., samples/sites were eliminated if identified as estimated, QC, media type other than surface water,
Superfund, landfill, failed laboratory QC, etc.).
Measured Concentrations in Published Literature
Using systematic review, the published literature yielded only a minimal amount of surface water
monitoring data for methylene chloride; a summary of the individual studies is provided in Table
2-18. Only two U.S. studies were identified. In one, a USGS nation-wide random survey of
rivers and reservoirs used for drinking water sources, methylene chloride was detected at 2.6
|ig/L in one out of 375 samples collected between 1999 and 2000 (detection limit of 0.2 |ig/L)
(USGS. 2003). In the other U.S. study, conducted in 1979-1981, methylene chloride was
detected in 93% of samples collected from the Eastern Pacific Ocean (Simeh et at.. 1983).
Concentrations ranged from below the detection limit (<0.0004) to 0.008 |ig/L, with a mean of
0.0031 |ig/L (n=30). No U.S. monitoring data were identified for year 2016.
The systematic review approach also identified data from various other countries and regions,
including Brazil, China, Japan, France, and Europe (Bianchi et at.. 2017; Ma et at.. 2014;
Christof et at. 2002; Ductos et at.. 2000; Yamamoto et at.. 1997). Collectively, these studies
encompass 332 samples collected between 1993 and 2013 from rivers and estuaries. The
Page 100 of 753

-------
reported methylene chloride concentrations range from below the detection limit to 134 |ig/L,
with reported central tendency values ranging from 0.0019 to 1.7 |ig/L. The highest
concentration was from an industrialized area of Osaka, Japan in 1993-1995 with a maximum
concentration of 134 |ig/L (Yamamoto et at. 1997). The next highest reported concentrations
were in the range of 4.5 to 5 |ig/L in industrialized or urban areas of China, France, and Europe
(1993-2011).
Table 2-18. Summary of Published Literature with Surface Water Monitoring Data
( on nl n
Site InToi-malion
Dale
Sampled
N
(Detection
l're(|iienc>)
( onccnlra
Kan^c
lion (,uti/l.)
Ccnlral
Tcndcno
SD)
Source
Dala
Qu;ili(>
Score
North America
U.S.
Nation-wide; Surface
water for drinking
water sources (rivers
and reservoirs)
1999-2000
375
(0.0027)
ND (<0.2) -
2.6
NR
(USGS.
2003)
Medium
U.S. to
Chile
Eastern Pacific Ocean
(California, U.S. to
Valparaiso, Chile)
1979-1981
30
(0.93)
ND (<0.0004)
- 0.008
Mean: 0.0031
0.0032
alTwO)
Medium
Europe and Asia
Brazil
Santo Antonio da
Patrulha, Tres Coroas,
and Parobe in the
Sinos River Basin;
River samples
collected from seven
points on the three
main rivers of the
Sinos River Basin
2012-2013
60
(0.72)
ND -0.0058
Mean: 0.0019
(Bianchi et
at. 20.1.7)
Medium
China
Daliao River (n=20
sites), heavily
industrialized
2011
20
(0.75)
ND (<0.675) -
4.47
Mean: 0.678
(Ma et a.L
20.1.4)
High
Europe
Estuaries of the
Scheldt, Thames,
Loire, Rhine
1997-1999
73
(1)
0.0003 -4.98
NR
(Christof et
a.L 2002)
High
France
Paris; River samples
(raw) collected from
the River Seine (n=14
stations), River Marne
(n=l station) and
River Oise (n=l
station). WWTPs are
located on the river.
1994-1995
43
(1)
0.016-4.92
Mean: 1.004 
1.218; Median:
0.473
(Duclos et
a.L 2000)
Medium
Japan
Osaka; Rivers and
estuaries (30 sites) in
industrialized city
1993-1995
136
(NR)
NR - 134
Median: 1.7
(Yamamoto
et al. 1997)
High
NR = Not reported
ND = Not detected; detection limit reported in parenthesis if available.
Page 101 of 753

-------
2.3.2.2 E-FAST Modeling Results
Summary
As discussed in Section 2.2, releases of methylene chloride were determined from two data
sources (TRI and DMR) for the 2016 calendar year and assigned to 14 TSCA condition of use
categories. Overall, 106 releases originating from 22 states were modeled, with the most in
California (15%) and New York (12%). The location of the actual releases, when accounting for
indirect dischargers, occurred in 21 U.S. states/territories (AL, AZ, CA, CT, GA, ID, IL, IN, KY,
LA, MD, MI, MO, NH, NJ, NY, OH, TN, TX, WA, WV). With respect to watersheds, the
releases occurred across 74 HUC-8 areas and 87 HUC-12 areas. At the HUC-8 level,
approximately three quarters of the HUCs contained only one identified facility release (73%),
and the remaining HUCs contained 2 to 5 facility releases. Direct and indirect dischargers
accounted for 77% and 23% of the total releases modeled, respectively. The majority of the
releases were modeled using site-specific NPDES codes (63%); surrogate NPDES codes were
used in only 9% of the cases, with the remaining cases {21%) run using a representative industry
sector SIC code. For releases modeled with a NPDES code (including a surrogate NPDES),
surface water concentrations were calculated for free-flowing water bodies in 82% of the cases,
and still water bodies for the remaining cases (18%). A detailed summary table by facility is
provided in Table Apx E-4.
Summary by Occupational Exposure Scenarios (OES)
A summary of the surface water concentration estimates modeled using E-FAST 2014 is
summarized by OES category in Table 2-21 for the maximum release scenario and Table 2-20
for the 20-day release scenario. Release estimates are based on reported 2016 releases to TRI
and DMR as summarized in Section 2.2.2. For the maximum days of release scenarios, surface
water concentrations under 7Q10 flow conditions ranged from 3.5E-07 to 1.8E+04 ppb. For the
20-day release scenarios, surface water concentrations ranged from 4.4E-06 to 5,857 ppb. On a
per facility basis, the 20-day release scenario yielded higher surface water concentrations than
the maximum day of release scenario.
Table 2-19. Summary of Surface Water Concentrations by Occupational Exposure
Scenarios (OES) for Maximum Days of Release Scenario		


Sum of


Surface \\ aler


Annual
Annual Release bv
Concentration

No. of
Releases
l-'acililv
(7QI0 I-low)

Releases
Modeled
(kg/site-vr)
(tig/1)
OES
Modeled
(kg/vr)
Mill
Max
Mill
Max
Manufacturing
20
162
8.28E-03
76
1.2E-05
5.0
Import and Repackaging
5
245
2.81E-02
144
5.1E-05
34
Processing as a Reactant
3
238
0.12
213
1.5E-02
0.26
Processing: Formulation
9
6,202
0.23
5,785
2.8E-06
1,659
Polyurethane Foam
1
2.3
2.3
2.3
1.1
1.1
Plastics Manufacturing
9
64
2.3E-02
28
4.2E-05
4.3
CTA Film Manufacturing
1
29
29
29
0.11
0.11
Page 102 of 753

-------

No. of
Releases
Sum of
Annual
Releases
Modeled
Annual Re
Kacil
(kg/sili
lease by
ity
-vr)
Surfai
(once
(7QH

-------
are 116 HUC-8 areas and 184 HUC-12 areas with either measured or predicted concentrations.
Table Apx E-5 provides a list of states/territories with facility releases (as mapped) and/or
monitoring sites.
Page 104 of 753

-------
Concentration Levels Concentration Type
	> 8146 (jg/L	~ Modeled - Direct Release (250 - 365 days/yr)
	1527 - 8145.9 |jg/L A Modeled - Indirect Release (250 - 365 days/yr)
32 - 1526.9 (jg/L o Measured - NWIS/STORET Monitoring Sites
	I 7 - 31.9 |jg/L	States with no modeled or measured concentrations
	1-6.9 |jg/L
< 1 M9/L
Not detected
l)j
300
 Miles
Figure 2-2. Surface Water Concentrations of Methylene Chloride from Releasing Facilities
(Maximum Days of Release Scenario) and Water Quality Exchange (WQX) Monitoring
Stations: Year 2016, Eastern U.S.
All indirect releases are mapped at the receiving facility unless the receiving facility is unknown.
Puerto Rico and the U.S. Virgin Islands not shown due to no modeled releases or measured monitoring information.
Page 105 of 753

-------
Concentration Levels Concentration Type
	> 8146 (jg/L	~ Modeled - Direct Release (250 - 365 days/yr)
	1527 - 8145.9 (jg/L A Modeled - Indirect Release (250 - 365 days/yr)
32- 1526.9 |jg/L
7-31.9 (jg/L
1 - 6.9 |jg/L
< 1 pg/L
Not detected
Measured - NWIS/STORET Monitoring Sites
States with no modeled or measured concentrations
Figure 2-3. Surface Water Concentrations of Methylene Chloride from Releasing Facilities
(Maximum Days of Release Scenario) and Water Quality Exchange (WQX) Monitoring
Stations: Year 2016, Western U.S.
All indirect releases are mapped at the receiving facility unless the receiving facility is unknown.
Alaska, Hawaii. Guam, N. Mariana Islands and American Somoa not shown due to no modeled releases or measured
monitoring information.
Page 106 of 753

-------
Concentration Levels
Concentration Type
HI Modeled - Direct Release (20 days/yr)
Measured - NWIS/STORET Monitoring Sites
>8146 |jg/L
1527- 8145.9 |jg/L
32 - 1526.9 |jg/L	1 States with no modeled or measured concentrations
7-31.9 |jg/L
1 - 6.9 |jg/L
< 1 |jg/L
Not detected
Figure 2-4. Concentrations of Methylene Chloride from Releasing Facilities (20 Days of
Release Scenario) and Water Quality Exchange (WQX)Monitoring Stations: Year 2016,
East U.S.
Puerto Rico and U.S. Virgin Islands not shown due to no modeled releases or measured monitoring information.
Page 107 of 753

-------
Concentration Levels
Concentration Type
~ Modeled - Direct Release (20 days/yr)
Measured - NWIS/STORET Monitoring Sites
>8146 |jg/L
1527- 8145.9 |jg/L
32 - 1526.9 (jg/L ' States with no modeled or measured concentrations
7-31.9 ng/L
1 -6.9 (jg/L
< 1 pg/L
Not detected

Figure 2-5. Concentrations of Methylene Chloride from Releasing Facilities (20 Days of
Release Scenario) and Water Quality Exchange (WQX) Monitoring Stations: Year 2016,
West U.S.
Alaska, Hawaii. Guam, N. Mariana Islands and American Somoa not shown due to no modeled releases or measured
monitoring information.
Page 108 of 753

-------
Superfund Analysis
An analysis of the 2016 dataset was conducted to determine if any monitoring stations may be
associated with nearby Superfund sites that may potentially contain methylene chloride releases,
and thus would not fall under the scope of this TSCA evaluation. In the dataset, six surface water
monitoring stations were within 1 mile of one or more Superfund sites in SEMS. Overall, 12
Superfund sites were identified, although only one of the 12 Superfund sites is on the National
Priority List (NPL), the others are identified as Non-NPL. All measured surface water
concentrations at the six monitoring sites were below the detection limit. For monitoring stations
that had detectable concentrations in 2016, the search was expanded to 5 miles. Sample
21NC03WQ-E3475000, located at Hominy Creek at Pond Rd in Asheville, NC, met this
criterion. However, the monitoring station is located on a separate tributary to the French Broad
River and its catchment does not include the Superfund site. Therefore, no monitoring stations
were removed from the geospatial analysis based on proximity to Superfund sites.
Co-location of Methylene Chloride Releasing Facilities and Monitoring Stations
The co-occurrence of methylene chloride releasing facilities and monitoring stations in a HUC is
shown in Figure 2-6. There are two adjacent HUC-8 areas (and one HUC-12) in Arizona that
have both measured and predicted concentrations. The associated facility and monitoring site
information are provided in Table 2-21. HUC 15070102 (Aqua Fria), has three direct releasing
facilities with modeled 7Q10 SWCs ranging from 0.11 to 7.99 |ig/L, and 7 monitoring stations
all with concentration less than the reported detection limit (0.8 to 5 |ig/L). Three of the
monitoring sites were 7.5 to 15.8 miles downstream of two facilities, the remaining monitoring
sites were neither up or downstream of facilities. HUC 15060106 (Lower Salt), has one direct
releasing facility with modeled 7Q10 SWCs ranging from 0.13 to 1.95 |ig/L, and 5 monitoring
stations all with concentration less than the reported detection limit (0.8 to 5 |ig/L).
As the measured concentrations were below the detection limit and the number of samples
collected was small, definitive conclusions could not be drawn on possible associations between
measured concentrations in surface water and predicted concentrations from facility releases.
Page 109 of 753

-------
Cake
Pleasant
AZ0020559
Theodore i
oosevelt Lake
AZ0020001
AZ0020524
Aqua Fria
15070102
Lower Salt
15060106
|AZUU2393l|
* Only one HUC-12 contains both
a facility and a monitoring station
U.S. Locations
Concentrations
Measured - NWIS/STORET Monitoring
 Not detected
Modeled - Direct Release (250-365 days/yr)
Maximum days of release: 0.0396 to 1.02 (jg/mL
~ 20 days of release: 0.72 to 18.59 fjg/mL
HUC-8 boundary
i i HUC-12 boundary*
r>~
50
I Miles
The National Map: National Hydrography Dataset. Data refreshed October, 2018.
Figure 2-6. Co-location of Methylene Chloride Releasing Facilities and Water Quality
Exchange (WQX) Monitoring Stations at the HUC 8 and HUC 12 Level
Page 110 of 753

-------
Table 2-21. Co-Location of Facility Releases and Monitoring Sites within HUC 8 Boundaries (Year 2016)
l-'acililics in III (
Monitoring Sites in III (




Measured





Surface \\ ater


Modeled "'QUI

No. or
Concentrations
Location C omments Kclali\c to
Silo
S\\(V (!i/l.)
Monitoring Site II)
Samples
(M/l.)
l-acilities1'
HUC 15070102: Aqua Fria
3 Direct Releasing Facilities

7 Monitoring Sites



1 . PIMA COUNTY - INA ROAD
365 days: 1.36*
USGS-333238112165201
1
ND (< 5)
Downstream of AZ0020001 (14 mi) and
WWTP; TUCSON, v4Z
20 days: 18.59*



AZ0020559 (15.8 mi)
NPDES: AZ0020001

USGS-333658112113200
1
ND (< 5)
Downstream of AZ0020001 (7.5 mi) and
AZ0020559 (9.4 mi)


USGS-333751112133801
1
ND (< 5)
Downstream of AZ0020001 (9.4 mi) and
AZ0020559 (11.4 mi)
2. 23RD AVENUE WWTP;
365 days: 0.26
USGS-09513925
1
ND (< 5)
Upstream or neither up or down stream
PHOENIX, AZ
20 days: 2.49




NPDES: AZ0020559

USGS-333407112045401d
3
ND (<0.3 - < 0.8)
Upstream or neither up or down stream


USGS-333840112123601
1
ND (< 5)
Upstream or neither up or down stream
3. APACHE JUNCTION WWTP
365 days: 0.0387




APACHE JUNCTION, AZ;
20 days: 0.72
USGS-334811112070700
3
ND (< 0.3 - < 4)
Upstream or neither up or down stream
NPDES: AZ0023931





HUC 15060106: Lower Salt
1 Direct Releasing Facility

5 Monitoring Sites



1. 91ST AVE WWTP;
365 days: 0.29
USGS-09512403cd
2
ND (<0.3 - < 0.8)
Neither up or down stream
TOLLESON, AZ
NPDES: AZ0020524
20 days: 4.52
USGS-332333112080301
USGS-332409111594101cd
3
2
ND (<0.3 - < 0.8)
ND (<0.3 - < 0.8)
Neither up or down stream
Neither up or down stream


USGS-332430112101001
2
ND (<0.3 - < 0.8)
Neither up or down stream


USGS-333557111594201
3
ND (< 0.3)
Neither up or down stream
a.	Concentrations leading to modeled days of exceedance are indicated by an asterisks (*).
b.	The number of miles between the facility and monitoring site are based on Euclidean distance.
c.	The monitoring sites are also co-located with the facility in the same HUC 12 (150601060306; City of Phoenix-Salt River).
d.	The monitoring sites are located within 1.02 to 1.08 miles of Superfund sites.
Page 111 of 753

-------
1.3.1 Co-location of Monitoring Stations and D M R/T RI/C D R/S u perfu nd Sites
Three monitoring sites in the 2016 dataset had detectable concentrations but were not co-located
with other identified methylene chloride-releasing facilities. As such these monitoring stations
were further characterized by evaluating their location with respect to any DMR (NPDES), TRI,
CDR, or Superfund site in 2016 as shown in Figure 2-7 and Figure 2-8.
I~~l HUC-8 boundary
i i HUC-12 boundary
\ Reservoir
21NC03WQ-B8484000
U.S. Location
Black
03030006
Lake IVaccamaw
SGS The National Map: National Hydrography Dataset. Data refreshed October. 2018.
Lake Waccamaw
Concentrations
Measured - NWIS/STORET
Monitoring Sites
 1.2 |jg/L
Facility Type
	CDR
r NPDES
	Superfund
Figure 2-7. Search of CDR, DMR (NPDES), Superfund, and TRI facilities in 2016 within
HUC-8 of Water Quality Portal (WQP) Station 21NC03WQ-AMS20161206 -B8484000.
Two samples with concentrations of 1.2 ppb were detected at this monitoring site on 2016.
Page 112 of 753

-------
'*
-------
into multiple PESS categories. For example, an individual may be exposed as a worker or ONU
and also outside of the workplace as a consumer.
Table 2-22. Crosswalk of Conditions of Use to Occupational and Consumer Scenarios
Assessed in the Risk Evaluation
l.ile ( >clo
Sl;ic
(;i lotion '
Siihciilejion h
Occnp;ilioiiiil Scoiiiii'io
CuMMinicr
Scen.irio
Manufacturing
Domestic
manufacturing
Manufacturing
Manufacturing
N/A

Import
Import
Repackaging
N/A
Processing
Processing as a
reactant
Intermediate in
industrial gas
manufacturing (e.g.,
manufacture of
fluorinated gases used
as refrigerants)
Processing as a Reactant
N/A


Intermediate for
pesticide, fertilizer, and
other agricultural
chemical manufacturing




Petrochemical
manufacturing




Intermediate for other
chemicals



Incorporated
into
formulation,
mixture, or
reaction
product
Solvents (for cleaning
or degreasing),
including
manufacturing of:
	All other basic
organic
chemical
	Soap, cleaning
compound and
toilet
preparation
Processing - Incorporation into
Formulation, Mixture, or Reaction
Product
N/A


Solvents (which
become part of product
formulation or mixture),
including
manufacturing of:
	All other
chemical
product and
preparation
	Paints and
coatings




Propellants and blowing
agents for all other
chemical product and

N/A
Page 114 of 753

-------
l.ile ( >clo
Sl;ic
(;i lotion '
Siihciilejion h
Occiipiilioiiiil Scoiiiii'io
CuMMinicr
Scen.irio


preparation
manufacturing


Propellants and blowing
agents for plastics
product manufacturing
Paint additives and
coating additives not
described by other
codes
Laboratory chemicals
for all other chemical
product and preparation
manufacturing
Laboratory chemicals
for other industrial
sectors
Processing aid, not
otherwise listed for
petrochemical
manufacturing
Adhesive and sealant
chemicals in adhesive
manufacturing
oil and gas drilling,
extraction, and support
activities
Repackaging
Solvents (which
become part of product
formulation or mixture)
for all other chemical
product and preparation
manufacturing
Repackaging
N/A
all other chemical
product and preparation
manufacturing
Recycling
Recycling
Waste Handling, Disposal, Treatment,
and Recycling
N/A
Distribution in
commerce
Distribution
Distribution
Repackaging
Industrial,
commercial
and consumer
uses
Solvents (for
cleaning or
degreasing)0
Batch vapor degreaser
(e.g., open-top, closed-
loop)
Batch Open-Top Vapor Degreasing
N/A
In-line vapor degreaser
(e.g., conveyorized,
web cleaner)
Conveyorized Vapor Degreasing
N/A
Cold cleaner
Cold Cleaning
N/A
Aerosol spray
degreaser/cleaner
Commercial Aerosol Products
(Aerosol Degreasing, Aerosol
Brake Cleaner,
Carbon Remover,
Page 115 of 753

-------
l.ile ( >clo
Sl;ic
(;i lotion '
Siihciilejion h
Occnp;ilioiiiil Scoiiiii'io
CuMMinicr
Scen.irio



Lubricants, Automotive Care
Products)
Carburetor
Cleaner, Coil
Cleaner,
Electronics
Cleaner, Engine
Cleaner, Gasket
Remover

Adhesives and
sealants
Single component glues
and adhesives and
sealants and caulks
Adhesives and Sealants
Adhesives,
Sealants

Paints and
coatings
Paints and coatings use
and paints and coating
Paints and Coatings
Brush Cleaner

including
commercial
paint and
coating
removers
removers, including
furniture refinisher
Paint and Coating Removers


Adhesive/caulk
removers
Adhesive and Caulk Removers
Adhesives
Removers

Metal products
not covered
elsewhere
Degreasers - aerosol
and non-aerosol
degreasers and cleaners
e.g., coil cleaners
Commercial Aerosol Products
(Aerosol Degreasing, Aerosol
Lubricants, Automotive Care
Products)
Miscellaneous Non-Aerosol Industrial
and Commercial Uses
Carbon Remover,
Coil Cleaner,
Electronics
Cleaner

Fabric, textile
and leather
products not
covered
elsewhere
Textile finishing and
impregnating/ surface
treatment products e.g.,
water repellant
Fabric Finishing
N/A

Automotive
care products
Function fluids for air
conditioners:
refrigerant, treatment,
leak sealer
Miscellaneous Non-Aerosol Industrial
and Commercial Uses
Automotive Air
Conditioning
Leak Sealer,
Automotive Air
Conditioning
Refrigerant


Interior car care - spot
remover
Commercial Aerosol Products
(Aerosol Degreasing, Aerosol
Lubricants, Automotive Care
Products)
N/A

Automotive
care products
Degreasers: gasket
remover, transmission
cleaners, carburetor
cleaner, brake
quieter/cleaner
Commercial Aerosol Products
(Aerosol Degreasing, Aerosol
Lubricants, Automotive Care
Products)
Brake Cleaner,
Carburetor
Cleaner, Engine
Cleaner, Gasket
Remover

Apparel and
footwear care
products
Post-market waxes and
polishes applied to
footwear e.g., shoe
polish
Commercial Aerosol Products
(Aerosol Degreasing, Aerosol
Lubricants, Automotive Care
Products)
N/A

Laundry and
dishwashing
products
Spot remover for
apparel and textiles
Spot Cleaning
N/A
Page 116 of 753

-------
l.ile ( >clo
Sl;ic
(;i lotion '
Siihciilejion h
Occnp;ilioiiiil Scoiiiii'io
CuMMinicr
Scen.irio

Lubricants and
greases
Liquid and spray
lubricants and greases
Commercial Aerosol Products
(Aerosol Degreasing, Aerosol
Lubricants, Automotive Care
Products)
Miscellaneous Non-Aerosol Industrial
and Commercial Uses
Brake Cleaner,
Carburetor
Cleaner, Engine
Cleaner, Gasket
Remover


Degreasers - aerosol
and non-aerosol
degreasers and cleaners

Building/
construction
materials not
covered
elsewhere
Cold pipe insulation
Commercial Aerosol Products
(Aerosol Degreasing, Aerosol
Lubricants, Automotive Care
Products)
Cold Pipe
Insulation

Solvents
(which become
part of product
formulation or
mixture)
All other chemical
product and preparation
manufacturing
Processing - Incorporation into
Formulation, Mixture, or Reaction
Product
N/A

Processing aid
not otherwise
listed
In multiple
manufacturing sectors6
Cellulose Triacetate Film Production
N/A

Propellants and
blowing agents
Flexible polyurethane
foam manufacturing
Flexible Polyurethane Foam
Manufacturing
N/A

Arts, crafts and
hobby
materials
Crafting glue and
cement/concrete
N/A
Adhesives

Other Uses
Laboratory chemicals -
all other chemical
product and preparation
manufacturing
Laboratory Use
N/A


Electrical equipment,
appliance, and
component
manufacturing
Miscellaneous Non-Aerosol Industrial
and Commercial Uses
N/A


Plastic and rubber
Plastic Product Manufacturing
N/A


products
Cellulose Triacetate Film Production
N/A


Anti-adhesive agent -
anti-spatter welding
aerosol
Commercial Aerosol Products
(Aerosol Degreasing, Aerosol
Lubricants, Automotive Care
Products)
Weld Spatter
Protectant


Oil and gas drilling,
extraction, and support
activities
Miscellaneous Non-Aerosol Industrial
and Commercial Uses
N/A


Toys, playground, and
sporting equipment -
including novelty
articles (toys, gifts, etc.)
Miscellaneous Non-Aerosol Industrial
and Commercial Uses
N/A
Page 117 of 753

-------
l.ile ( >clo
Sl;ic
(;i lotion '
Siihciilejion h
Occnp;ilioiiiil Scoiiiii'io
CuMMinicr
Scen.irio


Carbon remover,
lithographic printing
cleaner, wood floor
cleaner, brush cleaner
Lithographic Printing Plate Cleaning
Miscellaneous Non-Aerosol Industrial
and Commercial Uses
Brush Cleaner,
Carbon Remover
Disposal
Disposal
Industrial pre-treatment
Waste Handling, Disposal, Treatment,
and Recycling
N/A
Industrial wastewater
treatment
Publicly owned
treatment works
(POTW)
Underground injection
Municipal landfill
Hazardous landfill
Other land disposal
Municipal waste
incinerator
Hazardous waste
incinerator
Off-site waste transfer
a - These categories of conditions of use appear in the initial life cycle diagram, reflect CDR codes and broadly
represent conditions of use for methylene chloride in industrial and/or commercial settings,
b - These subcategories reflect more specific uses of methylene chloride.
c - Reported for the following sectors in the 2016 CDR for manufacturing of: plastic materials and resins, plastics
products, miscellaneous, all other chemical product and preparation (U.S. EPA. 20.1.6').
e -Reported for the following sectors in the 2016 CDR for manufacturing of: petrochemicals, plastic materials and
resins, plastics products, miscellaneous and all other chemical products (U.S. EPA. 20.1.6') which may include
chemical processor for polycarbonate resins and cellulose triacetate - photographic film, developer EPA's Use and
Market Profile for Methylene Chloride (U.S. EPA. 2017g).
N/A means these scenarios are not occupational or consumer conditions of use
2.4.1 Occupational Exposures
For the purpose of this assessment, EPA considered occupational exposure of the total workforce
of exposed users and non-users, which include but are not limited to male and female workers of
reproductive age who are >16 years of age. Female workers of reproductive age are >16 to less
than 50 years old. Adolescents (>16 to <21 years old) are a small part of this total workforce.
The occupational exposure assessment is applicable to and covers the entire workforce who are
exposed to methylene chloride.
Occupational Exposures Approach and Methodology Section 2.4.1.1 summarizes the
occupational acute and chronic inhalation exposure concentration and dermal dose models for
methylene chloride.
These models were then applied for the various industries and scenarios identified in Table 2-24.
Occupational Exposure Estimates by Scenario Section 2.4.1.2 summarizes air concentrations,
including both 8-hr time-weighted averages (TWA) and shorter-term averages, and inhalation
Page 118 of 753

-------
exposure concentrations and dermal doses by occupational exposure scenario (OES), and overall
summaries of model outputs and numbers of workers by OES.
The supplemental document titled "Risk Evaluation for Methylene Chloride (Dichloromethane,
DCM) CASRN: 75-09-2, Supplemental Information on Releases and Occupational Exposure
Assessment"(EPA. 2019b) provides background details on industries that may use methylene
chloride, worker activities, processes, numbers of sites and number of potentially exposed
workers. This supplemental document also provides detailed discussion on the values of the
exposure parameters and air concentrations and associated worker inhalation and dermal
exposure results presented in this section.
For each scenario, EPA distinguishes exposures for workers and occupational non-users (ONUs).
Normally, a primary difference between workers and ONUs is that workers may handle chemical
substances and have direct dermal contact with chemicals that they handle, while ONUs are
working in the general vicinity of workers but do not handle chemical substances and do not
have direct dermal contact with chemicals being handled by the workers. EPA expects that
ONUs may often have lower inhalation exposures than workers since they may be further from
the exposure source than workers. For inhalation, if EPA cannot distinguish ONU exposures
from workers, EPA assumes that ONU inhalation to be less than the inhalation estimates for
workers.
2.4.1.1 Occupational Exposures Approach and Methodology
This section summarizes the key occupational acute and chronic inhalation exposure
concentration and dermal dose models for methylene chloride. The supplemental document titled
" Risk Evaluation for Methylene Chloride (Dichloromethane, DCM) CASRN: 75-09-2,
Supplemental Information on Releases and Occupational Exposure Assessment" (EPA. 2019b)
provides detailed discussion on the values of the exposure parameters and air concentrations
input into these models.
Acute and Chronic Inhalation Exposure Concentrations Models
A key input to the acute and chronic models for occupational assessment is 8-hr time-weighted
average (TWA) air concentration. The 8-hr TWA air concentrations are time averaged to
calculate acute exposure, average daily concentration (ADC) for chronic, non-cancer risks, and
lifetime average daily concentration (LADC) for chronic, cancer risks.
Acute workplace exposures are assumed to be equal to the contaminant concentration in air (8-
or 12-hr TWA), per Equation 2-4.
(Eq. 2-4)
aec = _i_
AT acute
Where:
AEC = acute exposure concentration (mg/m3)
C = contaminant concentration in air (mg/m3, 8- or 12-hr TWA)
ED = exposure duration (8 or 12 hr/day)
Page 119 of 753

-------
ATacute = acute averaging time (8 or 12 hr)
ADC and LADC are used to estimate workplace chronic exposures for non-cancer and cancer
risks, respectively. These exposures are estimated as follows:
(Eq. 2-5)
C x ED x EF x WY
ADC orLADC= 	
AT orATC
Where:
ADC = average daily concentration (mg/m3) used for chronic non-cancer risk calculations
LADC = lifetime average daily concentration (mg/m3) used for chronic cancer risk
calculations
C = contaminant concentration in air (mg/m3, 8-hr TWA or 12-hr TWA)
ED = exposure duration (8 or 12 hr/day depending upon TWA of C)
EF = exposure frequency (250 days/yr for 8 hr/day ED or 167 days/yr for 12 hr/day
ED)
WY = exposed working years per lifetime (tenure values used to represent: 50th
percentile = 31; 95th percentile = 40)
AT = averaging time, non-cancer risks (WY x 365 days/yr x 24 hr/day)
ATC = averaging time, cancer risks (lifetime (LT) x 250 days/year x 8 hr/day for 8 hr/day
ED or 167 days/yr for 12 hr/day for 12 hr/day ED; where LT = 78 years); this
averaging time corresponds to the cancer benchmark as indicated in Chapter 3
HAZARDS
EPA reviewed workplace inhalation monitoring data collected by government agencies such as
OSHA and NIOSH, and monitoring data found in published literature (i.e., personal exposure
monitoring data and area monitoring data).
OSHA data are collected as part of compliance inspections at various types of facilities. Certain
industries are typically targeted based on national and regional emphasis programs. These
inspections are aimed at specific high-hazard industries or individual workplaces that have
experienced high rates of injuries and illnesses. Emphasis programs do use injury and illness
rates to inform their creation, but the bulk the sampling from programmed inspections would
come from scheduling that is based on objective or neutral selection criteria. Unprogrammed
inspections may also collect data and those inspections result from complaints, referrals, or
fatality/ catastrophe incidents. These data are compiled in the Chemical Exposure Health Data
(CEHD) database, available on the OSHA website, which contains the facility name, NAICS
code, sampling date, sampling time, and sample result. However, OSHA provided a subset of
data that also included worker activity descriptions and were verified for quality and were
subsequently used in the risk evaluation (OSHA. 2019). A comment from Dr. Finkel also
provided an OSHA dataset originating from a Freedom of Information Act (FOIA) request.
However, this dataset only included Standard Industrial Classification (SIC) codes which are less
specific than NAICS codes and also did not identify worker activities. Where possible, EPA
associated SIC codes with NAICS to pair the exposure data from Finkel ( ) with some OESs.
Page 120 of 753

-------
NIOSH data were primarily from Health Hazard Evaluations (HHEs) conducted at specific
processing or use sites.
Data were evaluated using the evaluation strategies laid out in the Application of Systematic
Review in TSCA Risk Evaluations (U.S. EPA. 2018a). and the evaluation details are shown in
two supplemental files: Risk Evaluation for Methylene Chloride, Systematic Review
Supplemental File: Data Quality Evaluation of Environmental Releases and Occupational
Exposure Data (EPA... 2019d) Risk Evaluation for Methylene Chloride, Systematic Review
Supplemental File: Data Quality Evaluation of Environmental Releases and Occupational
Exposure Common Sources (EPA. 2.019c). Where available, EPA used air concentration data
and estimates found in government or published literature sources. Where air concentration data
were not available, modeling estimates were used. Details on which models EPA used are
included in Section 2.4.1.2 for the applicable OESs and discussion of the uncertainties associated
with these models is included in Section 4.4.2. Beyond the modeling conducted for this Risk
Evaluation, EPA did not find reasonably available models and associated parameter sets to
conduct additional modeling.
EPA evaluated inhalation exposure for workers using personal monitoring data or modeled near-
field exposure concentrations. Since ONUs do not directly handle methylene chloride, EPA
reviewed personal monitoring data, modeled far-field exposure concentrations, and area
monitoring data in evaluating potential inhalation exposures for ONUs. Because modeled results
are typically intended to capture exposures in the near-field, modeling that does not contain a
specific far-field component are not considered to be suitable for ONUs. Area monitoring data
may potentially represent ONU exposures depending on the monitor placement and the intended
sample population.
Consideration of Engineering Controls and Personal Protective Equipment
OSHA requires and NIOSH recommends that employers utilize the hierarchy of controls to
address hazardous exposures in the workplace. The hierarchy of controls strategy outlines, in
descending order of priority, the use of elimination, substitution, engineering controls,
administrative controls, and lastly personal protective equipment (PPE). The hierarchy of
controls prioritizes the most effective measures first which is to eliminate or substitute the
harmful chemical (e.g., use a different process, substitute with a less hazardous material), thereby
preventing or reducing exposure potential. Following elimination and substitution, the hierarchy
recommends engineering controls to isolate employees from the hazard, followed by
administrative controls, or changes in work practices to reduce exposure potential (e.g., source
enclosure, local exhaust ventilation systems). Administrative controls are policies and procedures
instituted and overseen by the employer to protect worker exposures. As the last means of
control, the use of personal protective equipment (e.g., respirators, gloves) is recommended,
when the other control measures cannot reduce workplace exposure to an acceptable level. The
National Institute for Occupational Safety and Health (NIOSH) and the U.S. Department of
Labor's Bureau of Labor Statistics (BLS) conducted a voluntary survey of U.S. employers
regarding the use of respiratory protective devices between August 2001 and January 2002
(NIOSH... 2003). For additional information, please also refer to [Memorandum NIOSH BLS
Respirator Usage in Private Sector Firms. Docket # 1354 EPA-HQ-OPPT-2019-0500] (EPA.
2020a).
Page 121 of 753

-------
OSHA Standards and Respiratory Protection
The Occupational Safety and Health Administration (OSHA) Respiratory Protection Standard
(29 CFR 1910.134) provides a summary of respirator types by their assigned protection factor
(APF). Assigned Protection Factor (APF) "means the workplace level of respiratory protection
that a respirator or class of respirators is expected to provide to employees when the employer
implements a continuing, effective respiratory protection program" according to the
requirements of OSHA's Respiratory Protection Standard. Because methylene chloride may
cause eye irritation or damage, the OSHA standard for methylene chloride (29 CFR 1910.1052)
prohibits use of quarter and half mask respirators; additionally, only supplied air respirators
(SARs) can be used because methylene chloride may pass through air purifying respirators.
Respirator types and corresponding APFs indicated in bold font in Table 2-25. comply with the
OSHA standard for protection against methylene chloride. APFs are intended to guide the
selection of an appropriate class of respirators to protect workers after a substance is determined
to be hazardous, after an occupational exposure limit is established, and only when the exposure
limit is exceeded after feasible engineering, work practice, and administrative controls have been
put in place. For methylene chloride, the OSHA PEL is 25 ppm, or 87 mg/m3 as an 8-hr TWA,
and the OSHA short-term exposure limit (STEL) is 125 ppm, or 433 mg/m3 as a 15-min TWA.
For each occupational exposure scenario in Section 2.4.1.2, EPA compares the exposure data and
estimates to the PEL and STEL.
The current OSHA PEL was updated in 1997; prior to the change the OSHA PEL had been 500
ppm as an 8-hr TWA, which was 20 times higher than the current PEL of 25 ppm. EPA received
a public comment that included over 12,000 samples taken during OSHA or state health
inspections from 1984 to 2016 (Finkel. 2017). After the draft Risk Evaluation, EPA conducted a
more robust statistical analysis on these samples to evaluate how occupational exposures to
methylene chloride changed with time; in particular, any changes after the new PEL was fully
implemented (the 1997 OSHA rule required all facilities to comply with all parts of the rule no
later than April 9, 2000, which was three years after the final rule's effective date of April 10,
1997) (62 FR 1494). An appendix in the supplemental document titled "Risk Evaluation for
Methylene Chloride (Dichloromethane, DCM) CASRN: 75-09-2, Supplemental Information on
Releases and Occupational Exposure Assessment"(FP .-.0 h_!b) provides detailed discussion on
EPA's analysis. EPA filtered the samples to personal samples only, combined sequential samples
taken on the same worker, and calculated about 3,300 8-hr TWA exposures. To account for the
presence of non-detects, EPA replaced sample results of 0 ppm with the limit of detection (LOD)
divided by the square root of two. The exact LOD of the sampling and analysis method used in
each inspection conducted from 1984 to 2016 is not known. EPA estimated the exposure
concentrations for these data, following EPA/OPPT's Guidelines for Statistical Analysis of
Occupational Exposure Data (1994). which recommends using the LOD divided by the square
root of two if the geometric standard deviation of the data is less than 3.0 and LOD divided by
two if the geometric standard deviation is 3.0 or greater. OSHA method 80 for methylene
chloride (fully validated in 1990) reports an LOD of 0.201 ppm (Osha. 1990). NIOSH method
1005 for methylene chloride (issued January 15, 1998) reports an LOD of 0.4 micrograms per
sample, with a minimum and maximum air sample volume of 0.5 and 2.5 liters, respectively
(Niosii il!!J)- EPA calculated a range in LOD for the NIOSH method of 0.046 to 0.23 1 ppm.
Page 122 of 753

-------
For this analysis, EPA used an LOD of 0.046 ppm (the smallest of these three LOD values) and
an LOD divided by the square root of two of 0.0326 ppm.
EPA analyzed 1,407 and 1,471 8-hr TWA exposures measured prior to April 10, 1997 (pre-rule)
and after April 10, 2000 (post-rule). The arithmetic mean of the pre-rule and post-rule
distributions was 27.3 ppm and 17.9 ppm, respectively, a reduction of about 34%. The median of
the pre-rule and post-rule distributions was 3.7 ppm and 2.5 ppm, respectively, a reduction of
about 31%, similar to the reduction in the mean. EPA calculated the percentile ranks of 25 ppm
in the pre-rule and post-rule distributions: approximately 23% and 15% of the exposures
exceeded 25 ppm in the pre-rule and post-rule distributions, respectively. This is a reduction of
about 35%, similar to the reductions in the mean and median. While exposures in the
distributions showed consistent reductions of about 30% to 35%, this followed a reduction in the
PEL of 95%. Hence, a twentyfold reduction in the PEL resulted in only an approximately 1.5-
fold reduction in actual exposures. Due to the small reduction in exposures relative to the
reduction in PEL, EPA included the pre-rule samples as well as the post-rule samples in the
occupational exposure assessment to provide a more robust data set.
In addition to analyzing the entire distributions, EPA crosswalked reported SIC codes to 2017
NAICS codes and analyzed exposure trends in certain industry sectors. Table 2-23 summarizes
an analysis of industry codes representing the larger shares of the data set, while able 2-24
summarizes an analyses by OES (using the same NAICS codes used for the Number of Workers
analyses discussed Section 2.4.1.2). The summaries generally show a range in exposure
reductions across the industry sectors. The largest OES decreases were for spot cleaning (94.5%)
and fabric finishing (93.4%). On the other hand, exposures increased for plastics manufacturing
(617%) and aerosol degreasing (130%).
Table 2-23. Summary of Pre- and Post-Rule Exposure Concentrations for Industries with





Post-Rule Update, after all



Pre-Rule Update (prior to April
10,1997)
requirements in effect (after
April 10,2000)





%of


%of
Percent


Number
Arithmetic
Samples
Number
Arithmetic
Samples
Reduction
NAICS
NAICS
of
Mean
Above 25
of
Mean
Above
in Mean
Code
Description
Samples
(ppm)
ppm
Samples
(ppm)
25 ppm
(%)

Reupholstery
and Furniture







811420
Repair
36
98.73
53.8%
121
29.38
30.8%
70.2%

Wood Kitchen








Cabinet and







337110
Countertop
Manufacturing
35
9.91
11.7%
80
6.96
4.7%
29.8%

Unlaminated








Plastics Profile







326121
Shape
Manufacturing
76
35.00
30.2%
78
14.24
11.5%
59.3%

Polystyrene
Foam Product







326140
Manufacturing
12
19.27
31.9%
15
11.44
12.0%
40.6%
Page 123 of 753

-------

Motor Vehicle







336211
Body
Manufacturing
32
50.69
30.3%
6
3.04
N/Aa
94.0%

Commercial







323111
Printing
(except Screen
and Books)
55
9.54
11.1%
28
5.02
5.8%
47.4%
541380
Testing
Laboratories
16
2.43
N/Aa
29
3.65
2.2%
-50.6%b

Leather and







316110
Hide Tanning
and Finishing
10
8.14
5.8%
40
8.90
12.9%
-9.4%b
All NAICS Codes







Together

1,407
27.26
23.0%
1,471
17.86
15.0%
34%
Source of all samples: Finkel (2017)
a - N/A: Not applicable. There are no exposures above 25 ppm.
b - A negative reduction means the mean exposure increased from the pre-rule to post-rule periods.
able 2-24. Summary of Pre- and Post-Rule Exposure Concentrations Mapped to
Occupational Exposure Scenarios





Post-Rule Update, after all



Pre-Rule Update (prior to April
10,1997)
requirements in effect (after
April 10,2000)





Percent


Percent





of


of
Percent


Number
Arithmetic
Samples
Number
Arithmetic
Samples
Reduction

Potential
of
Mean
Above 25
of
Mean
Above
in Mean
OES
NAICS
Samples
(ppm)
ppm
Samples
(ppm)
25 ppm
(%)
Processing as a
Reactant
325120, 325320
12
15.2
16.7%
0
N/Aa
N/Aa
N/Aa
Processing -
Incorporation
325510, 325520,
325998







into








Formulation

23
46.2
52.2%
17
28.1
47.1%
39.3%
Aerosol
811111, 811112,







degreasing
811113, 811118,
811121, 811122,
811191, 811198,
811211, 811212,
811213, 811219,
811310, 811411,
811490, 451110,








441100
13
6.6
7.7%
15
15.1
13.3%
-129.7%
Adhesives and
326150, 332300,







Sealants
333900, 334100,
334200, 334300,
334400, 334500,
334600, 335100,
335200, 335300,
335900, 336100,
336200, 336300,
336400, 336500,
336600, 337100,








811420
256
44.8
32.0%
230
24.4
24.4%
45.5%
Page 124 of 753

-------
Paints and
Coatings
238320, 323113,
332000, 337100,
448100,713100,
811111
78
23.5
19.2%
169
12.3
7.7%
47.8%
Fabric
Finishing
313210, 313220,
313230, 313240,
313310, 313320
27
15.3
18.5%
6
1.0
0.0%
93.4%
Spot Cleaning
812320,812332
14
14.1
21.4%
3
0.8
0.0%
94.5%
Laboratory
Use
541380,621511
19
5.2
5.3%
36
3.2
2.8%
38.9%
Plastic Product
Mfg
325211, 325212,
325220, 325991,
326199
14
3.6
0.0%
20
26.1
5.0%
-616.9%
Lithographic
Printing Plate
Cleaning
323111
55
9.5
10.9%
28
5.0
7.1%
47.4%
Waste
Handling,
Disposal,
Treatment, and
Recycling
562211, 562213,
562920
15
6.0
6.7%
0
N/Aa
N/Aa
N/Aa
Source of all samples: Finkel (20.1.7)
a - N/A: Not applicable. Insufficient data points available,
b - N/A: Not applicable. There are no exposures above 25 ppm.
c - A negative reduction means the mean exposure increased from the pre-rule to post-rule periods. EPA does not
have reasonably available information to indicate possible reasons for increases.
EPA has sought additional data regarding exposures, particularly during the public comment
phases on the documents preceding the draft version of this risk evaluation (e.g., the methylene
chloride Section 6 rule and the problem formulation). With the exception of paint and coating
removers, EPA has not received information to date to indicate that workplace changes have
occurred broadly in particular sectors over the past 40 years.
Based on the protection standards, inhalation exposures may be reduced by a factor of 25, 50,
1,000, or 10,000, if respirators are required and properly worn and fitted. Air concentration data
are assumed to be pre-APF unless indicated otherwise in the source, and APFs acceptable under
the OSHA standards are not otherwise considered or used in the occupational exposure
assessment but are considered in the risk characterization and risk determination.
Table 2-25. Assigned Protection Factors for Respirators in OSHA Standard 29 CFR
1910.134 a
Type <>l' Respirator
Quarter
Mask
Mall" Mask
lull
l*~si copied*
1 Iclmct/
Mood
Loose-
rilling
l-'acepiece
1. Air Purifying Respirator
5
10
50


2. Powered Air-Purifying Respirator

50
1,000
25/1,000
25
Page 125 of 753

-------
Typo of Respirator
Quarter
Mask
1 hill'Mask
lull
l-'acepiece
11 ol 111 ol/
lloocl
Loose-
I'iuiii"
l-'accpiccc
3. Supplied-Air Respirator (SAR) or Airline
Respirator
	Demand mode
	Continuous flow mode
	Pressure-demand or other positive-
pressure mode

10
50
50
50
1,000
1,000


25/1,000
25


4. Self-Contained Breathing Apparatus
(SCBA)
	Demand mode
	Pressure-demand or other positive-
pressure mode

10
50
10,000
50
10,000




Note that only APFs indicated in bold are acceptable to OSHA for methylene chloride protection. Other respirators
from the Respiratory Protection Standard that are not acceptable for methylene chloride protection are indicated in
shaded cells.
Key Dermal Exposure Dose Models
Current EPA dermal models do not incorporate the evaporation of material from the dermis. The
dermal potential dose rate, Dexp (mg/day), is calculated as (EPA. 2013a):
(Eq. 2-6)
Dexp  S x Qu x Yderm x FT
Where:
S is the surface area of contact (cm2; defaults: 535 cm2 (central tendency); 1,070 cm2
(high end) = full area of one hand (central tendency) or two hands (high end), a 50th
percentile value for men > 21 yr (EPA. 201 la), the highest exposed population); note:
EPA has no data on actual surface area of contact with liquid and that the value is
assumed to represent an adequate proxy for a high-end surface area of contact with liquid
that may sometimes include exposures to much of the hands and also beyond the hands,
such as wrists, forearms, neck, or other parts of the body, for some scenarios.
Qu is the quantity remaining on the skin (mg/cm2-event; defaults: 1.4 mg/cm2-event
(central tendency); 2.1 mg/cm2-event (high end))
Yderm is the weight fraction of the chemical of interest in the liquid (0 < Yderm < 1)
FT is the frequency of events (integer number per day; default: 1 event/day); note: EPA
has described events per day (FT) as a primary uncertainty for dermal modeling in the
discussion of occupational dermal uncertainties in section 4.4.2.4. This discussion also
notes that this assumption likely underestimates exposure as workers often come into
repeat contact with the chemical throughout their workday.
Here Qu does not represent the quantity remaining after evaporation, but represents the quantity
remaining after the bulk liquid has fallen from the hand that cannot be removed by wiping the
skin (e.g., the film that remains on the skin).
Page 126 of 753

-------
One way to account for evaporation of a volatile solvent would be to add a multiplicative factor
to the EPA model to represent the proportion of chemical that remains on the skin after
evaporation,/abs (default: 0.08 for methylene chloride during industrial use; 0.13 for methylene
chloride during commercial use) (Miller et at... 2005):
(Eq. 2-7)
( Qu x fabs)
Dexp = S x	x Yderm x FT
This approach simply removes the evaporated mass from the calculation of dermal uptake.
Evaporation is not instantaneous, but the EPA model already has a simplified representation of
the kinetics of dermal uptake. The model assumes a fixed fractional absorption of the applied
dose; however, fractional absorption may vary and is dependent on various factors including
physical-chemical properties and wind speed. More information about this approach is presented
in Appendix E of the supplemental document titled " Risk Evaluation for Methylene Chloride
(Dichloromethane, DCM) CASRN: 75-09-2, Supplemental Information on Releases and
Occupational Exposure Assessments EPA. 2019b).
The occupational and consumer dermal exposure assessment approaches have a common
underlying methodology but use different parametric approaches for dermal exposures due to
different data availability and assessment needs. For example, the occupational approach
accounts for glove use using protection factors, while the consumer approach does not consider
glove use since consumers are not expected to use gloves constructed with appropriate materials.
The consumer approach (see Dermal section of Section 2.4.2.3.1) factors in time because
consumer activities as a function of exposure times to products are much better defined and
characterized, while duration of dermal exposure times for different occupational activities
across various workplaces are often not known.
Regarding glove use, data about the frequency of effective glove use - that is, the proper use of
effective gloves - is very limited in industrial settings. Initial literature review suggests that there
is unlikely to be sufficient data to justify a specific probability distribution for effective glove use
for a chemical or industry. Instead, the impact of effective glove use is explored by considering
different percentages of effectiveness.
EPA also made assumptions about glove use and associated protection factors (PF). Where
workers wear gloves, workers are exposed to methylene chloride-based product that may
penetrate the gloves, such as seepage through the cuff from improper donning of the gloves, and
if the gloves occlude the evaporation of methylene chloride from the skin. Where workers do not
wear gloves, workers are exposed through direct contact with methylene chloride.
Gloves only offer barrier protection until the chemical breaks through the glove material. Using a
conceptual model, Cherrie (2004) proposed a glove workplace protection factor - the ratio of
estimated uptake through the hands without gloves to the estimated uptake though the hands
while wearing gloves: this protection factor is driven by flux, and thus varies with time. The
European Centre For Ecotoxicology and Toxicology of Chemicals Targeted Risk Assessment
Page 127 of 753

-------
(ECETOC TRA) model represents the protection factor of gloves as a fixed, assigned protection
factor equal to 5, 10, or 20 (Marquart et at.. 20171 where, similar to the APR for respiratory
protection, the inverse of the protection factor is the fraction of the chemical that penetrates the
glove. Dermal doses without properly trained glove use are estimated in the occupational
exposure sections below and summarized in Table 2-26. Potential impacts of these protection
factors are presented as what-if scenarios in the dermal exposure summary Table 2-83. As
indicated in Table 2-26, use of protection factors above 1 is recommended only for glove
materials that have been tested for permeation against the methylene chloride-containing liquids
associated with the condition of use. EPA has not found information that would indicate specific
activity training (e.g., procedure for glove removal and disposal) for tasks where dermal
exposure can be expected to occur in a majority of sites in industrial only OESs, so the PF of 20
would usually not be expected to be achieved.
Table 2-26. Glove Protection Factors for Different Dermal Protection Strategies from
ECETOC TRA v3
Dermal Protection Characteristics
Setting
Protection
l-'actor. PK
a. No gloves used, or any glove / gauntlet without
permeation data and without employee training

1
b. Gloves with available permeation data indicating that the
material of construction offers good protection for the
substance
Industrial and
Commercial
Uses
5
c. Chemically resistant gloves (i.e., as b above) with "basic"
employee training

10
d. Chemically resistant gloves in combination with specific
activity training (e.g., procedure for glove removal and
disposal) for tasks where dermal exposure can be expected to
occur
Industrial Uses
Only
20
EPA also considered potential dermal exposure in cases where exposure is occluded. See further
discussion on occlusion in Appendix E of the Supplemental Information on Releases and
Occupational Exposure Assessment document (]	b).
It is important to note that the occupational dermal exposure approach and modeling differs from
that for consumer exposure approach outlined in Section 2.4.2.3.1 due to different data
availability and assessment needs and may result in different exposure values for similar
conditions of use.
Appendix F contains information gathered by EPA in support of understanding glove use for
pure methylene chloride and for paint and coatings removal using methylene chloride
formulations. This information may be generally useful for a broader range of uses of methylene
chloride and is presented for illustrative purposes. This appendix also contains a summary of
information on gloves from Safety Data Sheets (SDS) for methylene chloride and formulations
containing methylene chloride.
Page 128 of 753

-------
Risk Evaluation Definition of Central Tendency and High End
For most scenarios, EPA did not find enough data to determine statistical distributions of the
actual exposure parameters and concentration inputs to the inhalation and dermal models
described above. Within the distributions, central tendencies describe 50th percentile or the
substitute that most closely represents the 50th percentile. The high-end of a distribution
describes the range of the distribution above 90th percentile (U.S. EPA. 1992). Ideally, EPA
would use the 50th and 95th percentiles for each parameter. Where these statistics were
unknown, the mean or median (mean is preferable to median) served as substitutes for 50th
percentile and the high-end of ranges served as a substitute for 95th percentile. However, these
substitutes were highly uncertain and not ideal substitutes for the percentiles. EPA could not
determine whether these substitutes were suitable to represent statistical distributions of real-
world scenarios.
Exposures are calculated from the datasets provided in the sources depending on the size of the
dataset. For datasets with six or more data points, central tendency and high-end exposures were
estimated using the 50th percentile and 95th percentile. For datasets with three to five data points,
central tendency exposure was calculated using the 50th percentile and the maximum was
presented as the high-end exposure estimate. For datasets with two data points, the midpoint was
presented as a midpoint value and the higher of the two values was presented as a higher value.
Finally, data sets with only one data point presented the value as a what-if exposure. For datasets
including exposure data that were reported as below the limit of detection (LOD), EPA estimated
the exposure concentrations for these data, following EPA/OPPT's Guidelines for Statistical
Analysis of Occupational Exposure Data (1994) which recommends using the LOD / 25 if the
geometric standard deviation of the data is less than 3.0 and LOD / 2 if the geometric standard
deviation is 3.0 or greater (	0.
2.4.1_.2_Occupational Exposure Estimates by Scenario
Details of the occupational exposure assessments for each of the Occupational Exposure
Scenarios (OES) listed in Table 2-24, with one exception, are available in the supplemental
document titled " Risk Evaluation for Methylene Chloride (Dichloromethane, DCM) CASRN: 75-
09-2, Supplemental Information on Releases and Occupational Exposure Assessment" (EPA.
2019b). The exception is for Paint and Coating Removers, which are covered in Appendix L.
The following subsections contain a summary of inhalation and dermal estimates for each OES,
assuming no PPE use. Details on the inhalation and dermal estimates as well as process
descriptions, numbers of sites and potentially exposed workers, and worker activities for each
OES are available in the supplemental document (	19b). Lists of all inhalation
monitoring data found in data sources and associated systematic review data quality ratings are
available in Appendix A of this supplemental document. EPA could not determine whether PPE
or engineering controls were used for some settings where monitoring was conducted.
Key uncertainties toward exposure estimates in these scenarios are summarized in Section 4.4.2.
Table 2-27 presents estimated numbers of workers in the OESs assessed for methylene chloride.
Where available, EPA used publicly available data (typically CDR) to provide a basis to estimate
Page 129 of 753

-------
the number of sites, workers and ONUs. EPA supplemented the available CDR data with U.S.
economic data using the following method:
1.	Identify the North American Industry Classification System (NAICS) codes for the
industry sectors associated with these uses.
2.	Estimate total employment by industry/occupation combination using the Bureau of
Labor Statistics' Occupational Employment Statistics data (BLS Data).
3.	Refine the OES estimates where they are not sufficiently granular by using the U.S.
Census' Statistics of US Businesses (SUSB) (SUSB Data) data on total employment by
6-digit NAICS.
4.	Use market penetration data to estimate the percentage of employees likely to be using
methylene chloride instead of other chemicals.
5.	Where market penetration data are not available, use the estimated workers/ONUs per
site in the 6-digit NAICS code and multiply by the number of sites estimated from CDR,
TRI, or National Emissions Inventory (NEI).
EPA combined the data generated in Steps 1 through 5 to produce an estimate of the number of
employees using methylene chloride in each industry/occupation combination (if available), and
then summed these to arrive at a total estimate of the number of employees with exposure within
the occupational exposure scenario. More details on the data are provided in the supplemental
document titled " Risk Evaluation for Methylene Chloride (Dichloromethane, DCM) CASRN: 75-
09-2, Supplemental Information on Releases and Occupational Exposure Assessment" CEP A.
2019b).
Table 2-27. Estimated Numbers of Workers in the Assessed Industry Scenarios for
Methylene Chloride
Occupational Kxposure Scenario
N umber of W orkers
Number of ONI s
Manufacturing
1,200
*
Processing as a Reactant
460
120A
Processing - Incorporation into
Formulation
4,500
*
Repackaging
2,300
*
Batch Open-Top Vapor Degreasing
270
*
Conveyorized Vapor Degreasing
180
*
Cold Cleaning
95,000
*
Aerosol Degreasing/Lubricants
250,000
29,000
Adhesives
2,700,000
810,000
Paints and Coatings
1,800,000
340,000
Adhesive and Caulk Removers
190,000
18,000
Fabric Finishing
19,000
12,000
Page 130 of 753

-------
Occupational Kxposure Scenario
N il in her of Workers
Number ol'OMs
Spot Cleaning
76,000
7,900
CTA Manufacturing
700
*
Flexible PU Foam Manufacturing
9,600
2,700
Laboratory Use
17,000
150,000
Plastic Product Manufacturing
210,000
90,000
Lithographic Printing Cleaner
40,000
19,000
Miscellaneous Non-Aerosol Industrial and
Commercial Use (Cleaning Solvent)
<1,400,000
*
Waste Handling, Disposal, Treatment, and
Recycling
12,000
7,600
* - Based on EPA's analysis, the data for worker and ONUs and could not be distinguished.
A - One data source distinguished ONUs from workers and the other source did not.
2.4.1.2.1 Manufacturing
The Halogenated Solvents Industry Alliance (HSIA) provided personal monitoring data from
2005 through 2018 at two manufacturing facilities for a variety of worker activities (Halogenated
Solvents Industry Alliance. 2018). Lists of all inhalation monitoring data found in data sources
and associated systematic review data quality ratings are available in Appendix A of the
supplemental document" Risk Evaluation for Methylene Chloride (Dichlorome thane, DCM)
CASRN: 75-09-2, Supplemental Information on Releases and Occupational Exposure
Assessment"(EPA. 2019b).
Overall, 136 8-hr TWA and 149 12-hr TWA personal monitoring data samples were available;
EPA calculated the 50th and 95th percentile 8- and 12-hr TWA concentrations to represent a
central tendency and high-end estimate of potential occupational inhalation exposures,
respectively, for this scenario. Both the central tendency and high-end 8- and 12-hr TWA
exposure concentrations for this scenario are approximately one order of magnitude below the
OSHA Permissible Exposure Limit (PEL) value of 87 mg/m3 (25 ppm) as an 8-hr TWA. All data
points were post-PEL rule (see Section 2.4.1.1 for pre-PEL, transition, and post-PEL rule
periods).
Using these 8-hr TWA exposure concentrations, EPA calculated the ADC and LADC as
described in Section 2.4.1.1 and are summarized in Table 2-28.
Page 131 of 753

-------
Table 2-28. Worker Exposure to Methylene Chloride During Manufacturing3

N il in her of
Samples
Central
Tendency
(ing/nr*)
Iligh-Knd
(ing/nr')
Data Quality
Ualing of
Associated Air
Concentration Data
8-hr TWA Results
8-hr TWA Exposure
Concentration
136
0.36
4.6
High
Average Daily Concentration
(ADC)
0.08
1.1
Lifetime Average Daily
Concentration (LADC)
0.14
2.4
12-hr TP
7A Results
12-hr TWA Exposure
Concentration
149
0.45
12
High
Average Daily Concentration
(ADC)
0.15
4.1
Lifetime Average Daily
Concentration (LADC)
0.27
9.3
Sources: Halogenated Solvents Industry Alliance (20.1.8)
a - No data for ONUs were found; EPA assumes that ONU exposures are less than worker exposures.
Table 2-29 summarizes available short-term exposure data for workers provided by HSIA
(Halogenated Solvents Industry Alliance. 2.018).
Table 2-29. Short-1
"erm Wor
ter Exposure to Met
lylene Chloride During Manufacturing




Data Quality

N il in her


Ualing of

of
Central Tendency
Iligh-Knd
Associated Air

Samples
(mg/m3)
(ing/nr')
Concentration Data
15-min a
148
9.6
180

30-min b
1
2.6
High
1-hrc
4
4.3
16

Source: Halogenated Solvents Industry Alliance (20.1.8).
a - EPA evaluated 148 samples, with durations ranging from 15 to 22 minutes, as 15-minute exposures.
b - EPA evaluated one sample, with a duration of 35 minutes, as a 30-minute exposure.
c - EPA evaluated four samples, with durations ranging from 50 to 55 minutes, as 1-hour exposures.
Note: The OSHA Short-term exposure limit (STEL) is 433 mg/m3 as a 15-min TWA. One sample of 486 mg/m3
among the 148 15-min samples exceeded this limit, and the remaining 147 samples were below this limit.
EPA has not identified personal or area data on or parameters for modeling potential ONU
inhalation exposures from methylene chloride manufacturing. Since ONUs do not directly handle
methylene chloride (otherwise they would be considered workers), ONU inhalation exposures
could be lower than worker inhalation exposures. Information on activities where ONUs may be
Page 132 of 753

-------
present are insufficient to determine the proximity of ONUs to workers and sources of emissions,
so relative exposure of ONUs to workers cannot be quantified.
Table 2-30 presents estimated dermal exposures during domestic manufacturing.
Table 2-30. Summary of Dermal Exposure Doses to Methylene Chloride for Manufacturing
Occupational
Kxposure
Scenario
I se Selling
(Industrial vs.
Com in ercial)
.Maximum
Weight
Traction.
^ iIitih'1
Dermal K\|
(mg/
Central
Tendency
)osurc Dose
.lay)1'
High KihI
Calculated
Traction
Absorbed.
r iiiiN
Manufacturing
Industrial
1.0
60
180
0.08
a - EPA assumes methylene chloride manufactured at 100% concentration.
b - Conditions where no gloves are used, or for any glove / gauntlet use without permeation data and without
employee training (PF = 1).
Potential impacts of protection factors are presented as what-if scenarios in the dermal exposure summary Table
2-85.
In summary, dermal and inhalation exposures are expected for this scenario. EPA has not
identified additional uncertainties for this scenario beyond those discussed in Section 4.4.2.
EPA considered the assessment approach, the quality of the data, and uncertainties in assessment
results to determine a level of confidence for the 8-hr TWA data. For the inhalation air
concentration data, the primary strengths include the assessment approach, which is the use of
monitoring data, the highest of the inhalation approach hierarchy. These monitoring data include
136 8-hr and 149 12-hr data points from 1 source, and the data quality ratings from systematic
review for these data were high. All of the data points were post-PEL rule. The primary
limitations of these data include the uncertainty of the representativeness of these data toward the
true distribution of inhalation concentrations for the industries and sites covered by this scenario.
Based on these strengths and limitations of the inhalation air concentration data, the overall
confidence for these 8-hr TWA data in this scenario is medium to high. The overall confidence
of the dermal dose results is medium (full discussion in Section 2.4.1.3).
2.4.1.2.2 Processing as a Reactant
HSIA provided monitoring data (15 data points) from 2010 through 2017 from a fluorochemical
manufacturing facility, where methylene chloride could be used as an intermediate for the
production of fluorocarbon blends (Halogenated Solvents Industry Alliance. 2018). Finkel
(201?) also submitted workplace monitoring data obtained from a FOIA request of OSHA. EPA
extracted relevant monitoring data by crosswalking the Standard Industrial Classification (SIC)
codes in the dataset with the NAICS codes for Industrial Gas Manufacturing and Pesticide and
Other Agricultural Chemical Manufacturing. For the set of 14 data points, 8-hr TWA exposure
concentrations ranged from 0.11 to 301 mg/m3. Worker activity information was not available;
therefore, it was not possible to specifically attribute the exposures to the use of methylene
chloride as a reactant, nor to distinguish workers from ONUs. While there may be additional
activities at these sites, such as use of methylene chloride as a cleaning solvent that contribute to
methylene chloride exposures, EPA assumes that exposures are representative of worker
Page 133 of 753

-------
exposure during processing as a reactant. Sample times also varied; EPA assumed that any
measurement longer than 15 minutes was done to assess compliance with the 8-hr TWA PEL, as
opposed to the 15-minute STEL, and averaged all applicable data points over 8 hours. Lists of all
inhalation monitoring data found in data sources and associated systematic review data quality
ratings are available in Appendix A of the supplemental document" Risk Evaluation for
Methylene Chloride (Dichloromethane, DCM) CASRN: 75-09-2, Supplemental Information on
Releases and Occupational Exposure Assessment" (EPA. 2019b).
Overall, 29 8-hr TWA personal monitoring data samples were available; EPA calculated the 50th
and 95th percentile 8-hr TWA concentrations to represent a central tendency and worst-case
estimate of potential occupational inhalation exposures, respectively, for this scenario. The
central tendency 8-hr TWA exposure concentration is more than an order of magnitude lower
than the OSHA PEL value of 87 mg/m3 (25 ppm) as an 8-hr TWA, while the high-end 8-hr TWA
exposure concentrations for this scenario is higher than the OSHA PEL. Of the 29 data points, 12
of the data points were pre-PEL rule, 2 data points were during the transition period, while 15
data points were post-PEL rule (see Section 2.4.1.1 for pre-PEL, transition, and post-PEL rule
periods). Based on available short-term exposure data, 10-minute TWAs could be up to 350
mg/m3 during specific operations such as filter changing, charging and discharging, etc.
Table 2-31 presents the calculated the AEC, ADC, and LADC for these 8-hr TWA exposure
concentrations, as described in Section 2.4.1.1.
Table 2-31. Worker Exposure to Methylene Chloride During Processing as a Reactant
During Fluorochemicals Manufacturing3				

N il in her
of
Samples
Central
Tendency
(ing/nr*)
High End
(mg/nr')
Data Qualify
Rating of
Associated Air
Concentration
Data
8-hr TWA Exposure
Concentration
29
1.6
110
High and Medium
Average Daily Concentration
(ADC)
0.37
25
Lifetime Average Daily
Concentration (LADC)
0.65
55
Sources: Halogenated Solvents Industry Alliance (20.1.8): Finket (20.1.7)
a - No data for ONUs were found; EPA assumes that ONU exposures are less than worker exposures.
Table 2-32 summarizes available short-term exposure data available for "other chemical
industry" and during drumming at a pesticide manufacturing site.
Page 134 of 753

-------
Table 2-32. Summary of Personal Short-Term Exposure Data for Methylene Chloride
During Processing as a Reactant 				
Occupational
Kxposurc
Scenario
Source
Worker
Activity
.Methylene
Chloride
Short-Term
Concentration
(ing/nr*)
Exposure
Duration
(mill)
Data Quality
Killing of
Associated
Air
Concent rat ion
Data
Other
Chemical
Industry
TNO (CIYO)
filter
changing,
charging
and
discharging,
etc.
350 (max)
10a
Low
Pesticides
Mfg
Olin C >79)
Drumming
1,700
25 b
Medium
a - EPA evaluated as a 15-minute exposure,
b - EPA evaluated as a 30-minute exposure
Note: The OSHA Short-term exposure limit (STEL) is 433 mg/m3 as a 15-min TWA.
EPA has not identified personal data on or parameters for modeling potential ONU inhalation
exposures. Limited area monitoring data were identified (see Appendix A.2 of the supplemental
document titled " Risk Evaluation for Methylene Chloride (Dichlorome thane, DCM) CASRN: 75-
09-2, Supplemental Information on Releases and Occupational Exposure Assessment" (EPA.
2019b)). However, the representativeness of these data for ONU exposures is not clear because
of uncertainty concerning the intended sample population and the selection of the specific
monitoring location. EPA assumed that the area monitoring data were not appropriate surrogates
for ONU exposure due to lack of necessary metadata , such as monitor location and distance
from worker activities, to justify its use. ONUs are employees who work at the facilities that
process and use methylene chloride, but who do not directly handle the material. ONUs may also
be exposed to methylene chloride but are expected to have lower inhalation exposures and are
not expected to have dermal exposures. ONUs for this condition of use may include supervisors,
managers, engineers, and other personnel in nearby production areas. Since ONUs do not
directly handle formulations containing methylene chloride (otherwise they would be considered
workers), EPA expects ONU inhalation exposures to be lower than worker inhalation exposures.
Information on processes and worker activities is insufficient to determine the proximity of
ONUs to workers and sources of emissions, so relative exposure of ONUs to workers cannot be
quantified using modeling.
Table 2-33 presents modeled dermal exposures during processing as a reactant.
Page 135 of 753

-------
Table 2-33. Summary of Dermal Exposure Doses to Methylene Chloride for Processing as a
Reactant
Occupational
Kxposure
Scenario
I se Selling
(Industrial vs.
Com in ercial)
.Maximum
Weight
Traction.
^ iIitih'1
Dermal K\|
(mg/
Central
Tendency
)osurc Dose
.lay)1'
High KihI
Calculated
Traction
Absorbed.
r iiiiN
Processing as a
Reactant
Industrial
1.0
60
180
0.08
a - EPA assumes methylene chloride is received at 100% concentration.
b - Conditions where no gloves are used, or for any glove / gauntlet use without permeation data and without
employee training (PF = 1).
Potential impacts of protection factors are presented as what-if scenarios in the dermal exposure summary Table
2-85.
In summary, dermal and inhalation exposures are expected for this scenario. EPA has described
uncertainties for this scenario in Section 4.4.2.
EPA considered the assessment approach, the quality of the data, and uncertainties in assessment
results to determine a level of confidence for the 8-hr TWA data. For the inhalation air
concentration data, the primary strengths include the assessment approach, which is the use of
monitoring data, the highest of the inhalation approach hierarchy. These monitoring data include
29 data points from 2 sources, and the data quality ratings from systematic review for these data
were high and medium. The primary limitations of these data include the age of the data (12 of
the data points were pre-PEL rule, 2 data points were during the transition period, while 15 data
points were post-PEL rule) and uncertainty of the representativeness of these data toward the true
distribution of inhalation concentrations for the industries and sites covered by this scenario. As
discussed earlier in this section, key metadata such as worker activity and sampling descriptions
were not available to specifically attribute exposures to the use of methylene chloride as a
reactant or to determine whether sampled activities were representative of full-shift exposures.
The analysis of pre- and post-rule OSHA data (summarized in Table 2-26) did not have enough
data to compare pre- to post-rule mean exposure concentrations for this OES. Based on these
strengths and limitations of the inhalation air concentration data, the overall confidence for these
8-hr TWA data in this scenario is low. The overall confidence of the dermal dose results is
medium (full discussion in Section 2.4.1.3).
2.4.1.2.3 Processing - Incorporation into Formulation, Mixture, or Reaction
Product
Finkel (2017) submitted workplace monitoring data obtained from a FOIA request of OSHA.
EPA extracted relevant monitoring data by crosswalking the Standard Industrial Classification
(SIC) codes in the dataset with the NAICS codes for Paint and Coating Manufacturing and
Adhesives Manufacturing. For the set of 45 data points, 8-hr TWA exposure concentrations
ranged from 0.86 to 559 mg/m3. Worker activity information was not available; therefore, it was
not possible to specifically attribute the exposures to formulation processes using methylene
chloride, nor to distinguish workers from ONUs. While additional activities are possible at these
sites, such as use of methylene chloride as a reactant or as a cleaning solvent that contribute to
Page 136 of 753

-------
methylene chloride exposures, EPA assumes that exposures are representative of worker
exposures during processing methylene chloride into formulation. Sample times also varied;
EPA assumed that any measurement longer than 15 minutes was done to assess compliance with
the 8-hr TWA PEL, as opposed to the 15-minute STEL, and averaged all applicable data points
over 8 hours. Additional discussion of data treatment is included in Appendix H. U.S. EPA
Q%5) also provided exposure data for packing at paint/varnish and cleaning products sites,
ranging from 52 mg/m3 (mixing) to 2,223 mg/m3 (valve dropper). Lists of all inhalation
monitoring data found in data sources and associated systematic review data quality ratings are
available in Appendix A of the supplemental document" Risk Evaluation for Methylene Chloride
(Dichloromethane, DCM) CASRN: 75-09-2, Supplemental Information on Releases and
Occupational Exposure Assessment" CEP A. 2019b).
Overall, 55 personal monitoring data samples were available; EPA calculated the 50th and 95th
percentile 8-hr TWA concentrations to represent a central tendency and high-end estimate of
potential occupational inhalation exposures, respectively, for this scenario. The central tendency
8-hr TWA exposure concentration for this scenario is slightly higher than the OSHA PEL value
of 87 mg/m3 (25 ppm) as an 8-hr TWA, while the high-end estimate is approximately six times
higher. Of the 55 data points, 33 of the data points were pre-PEL rule, 7 data points were during
the transition period, while 15 data points were post-PEL rule (see Section 2.4.1.1 for pre-PEL,
transition, and post-PEL rule periods).
Using these 8-hr TWA exposure concentrations, EPA calculated the ADC and LADC as
described in Section 2.4.1.1 and are listed in Table 2-34.
Table 2-34. Worker Exposure to Methylene Chloride During Processing - Incorporation
into Formulation, Mixture, or Reacl
tion Product"




Data Qualify




Rating of

N il in her
Central

Associated Air

ol'
Tendency
lligh-lnd
Concentration

Samples
(mg/nr')
(mg/m5)
Data
8-hr TWA Exposure Concentration

100
540

Average Daily Concentration
(ADC)
55
23
120
High and
Medium
Lifetime Average Daily
Concentration (LADC)

40
280
Sources: EPA (.1.985): Finite! (20.1.7)
a - No data for ONUs were found; EPA assumes that ONU exposures are less than worker exposures.
TNO (CIVO) (1999) indicated that the peak exposure during filling may be up to 180 mg/m3 but
did not provide exposure duration. Therefore, this exposure concentration was not used in the
assessment.
EPA has not identified personal or area data on or parameters for modeling potential ONU
inhalation exposures. Since ONUs do not directly handle formulations containing methylene
chloride, ONU inhalation exposures could be lower than worker inhalation exposures.
Page 137 of 753

-------
Information on processes and worker activities are insufficient to determine the proximity of
ONUs to workers and sources of emissions, so relative exposure of ONUs to workers cannot be
quantified.
Table 2-35 presents modeled dermal exposures during processing - incorporation into
formulation, mixture or reaction product.
Table 2-35. Summary of Dermal Exposure Doses to Methylene Chloride for Processing -
Incorporation into Formulation, Mixture, or Reaction Product.	
Occupational
Kxposure
Scenario
I se Setting
(Industrial vs.
Commercial)
.Maximum
Weight
l-'raction.
^ ilei in'1
Dermal K\|
(mg/
Central
Tendency
)osurc Dose
.lay)1'
High I nd
Calculated
l-'raction
Absorbed.
r iiiiN
Processing -
Incorporation
into Formulation,
Mixture, or
Reaction Product
Industrial
1.0
60
180
0.08
a - EPA assumes methylene chloride is received at 100% concentration.
b - Conditions where no gloves are used, or for any glove / gauntlet use without permeation data and without
employee training (PF = 1).
Potential impacts of PFs are presented as what-if scenarios in the dermal exposure summary Table 2-85.
In summary, dermal and inhalation exposures are expected for this scenario. EPA has described
uncertainties for this scenario in Section 4.4.2.
EPA considered the assessment approach, the quality of the data, and uncertainties in assessment
results to determine a level of confidence for the 8-hr TWA data. For the inhalation air
concentration data, the primary strengths include the assessment approach, which is the use of
monitoring data, the highest of the inhalation approach hierarchy. These monitoring data include
55 data points from 2 sources, and the data quality ratings from systematic review for these data
were high. The primary limitations of these data include the age of the data (33 of the data points
were pre-PEL rule, 7 data points were during the transition period, while 15 data points were
post-PEL rule) and uncertainty of the representativeness of these data toward the true distribution
of inhalation concentrations for the industries and sites covered by this scenario. As discussed
earlier in this section, key metadata such as worker activity and sampling descriptions were not
available to specifically attribute exposures to the formulation of methylene chloride-containing
products or to determine whether sampled activities were representative of full-shift exposures.
A comparison of pre- and post-rule OSHA data (summarized in Table 2-26) shows that mean
exposure concentrations decreased by 39.3% from pre- to post-rule. Based on these strengths and
limitations of the inhalation air concentration data, the overall confidence for these 8-hr TWA
data in this scenario is low. The overall confidence of the dermal dose results is medium (full
discussion in Section 2.4.1.3).
Page 138 of 753

-------
2.4.1.2.4 Repackaging
EPA found limited inhalation monitoring data for repackaging from published literature sources.
A 1986 Industrial Hygiene (IH) study at Unocal Corporation found full-shift exposures during
filling drums, loading trucks, and transfer loading to be between 6.0 and 137.8 mg/m3 (5 data
points) (Unocal Corporation. 1986). Lists of all inhalation monitoring data found in data sources
and associated systematic review data quality ratings are available in Appendix A of the
supplemental document" Risk Evaluation for Methylene Chloride (Dichloromethane, DCM)
CASRN: 75-09-2, Supplemental Information on Releases and Occupational Exposure
Assessment"(EPA. 2019b).
Because only five 8-hr TWA data points were available, EPA assessed the median value of 8.8
mg/m3 as the central tendency, and the maximum reported value of 137.8 mg/m3 as the high-end
estimate of potential occupational inhalation exposures, respectively, for this scenario. The
central tendency 8-hr TWA exposure concentration for this scenario is approximately 10 times
lower the OSHA PEL value of 87 mg/m3 (25 ppm) as an 8-hr TWA, while the high-end estimate
is approximately 1.5 times higher. All data points were pre-PEL rule (see Section 2.4.1.1 for
pre-PEL, transition, and post-PEL rule periods).
Using these 8-hr TWA exposure concentrations, EPA calculated the ADC and LADC. The
results of these calculations are shown in Table 2-36.
Table 2-36. Worker Exposure to
Methylene C
lloride During Repackaging3

Number of
Samples
Central
Tendency
(nig/nr*)
lligh-lnd
(ing/nr')
Data Qualify Rating
of Associated Air
Concentration Data
8-hr TWA Exposure Concentration
5
8.8
140
Medium
Average Daily Concentration (ADC)
2.0
31
Lifetime Average Daily
Concentration (LADC)
3.5
71
Source: Unocal Corporation (.1.986)
a - No data for ONUs were found; EPA assumes that ONU exposures are less than worker exposures.
Table 2-37 summarizes available short-term exposure data available from the same OSHA
source identified above for the 8-hr TWA data.
Table 2-37. Summary of Personal Short-Term Exposure Data for Methylene Chloride
During Repackaging					
Occupational
Kxposure
Scenario
Source
Worker
Activity
Methylene
Chloride
Short-Term
Concentration
(nig/in^)
Kxposurc
Duration
(mill)
Data Quality
Rating of
Associated Air
Concent rat ion
Data
Distribution

Transfer loading
from truck to
0.35
30 a
Medium
Page 139 of 753

-------



.Methylene

Data Quality



Chloride

Rating of
Occupational


Short-Term
Kxposurc
Associated Air
Kxposure

Worker
Concentration
Duration
Concent rat ion
Scenario
Source
Activity
(ing/nr*)
(mill)
Data


storage tank
(4,100 gallons)




Unocal
Corporation
0986)
Truck loading
(2,000 gallons)
330
50 b


Truck loading
(800 gallons)
35
30a



Truck loading
(250 gallons)
30
47 b

a - EPA evaluated two samples with durations of 30 minutes each, as 30-minute exposures,
b - EPA evaluated two samples with durations of 47 and 50 minutes, as a 1-hr exposures.
Note: The OSHA STEL is 433 mg/m3 as a 15-min TWA.
EPA has not identified personal or area data on or parameters for modeling potential ONU
inhalation exposures. ONUs are employees who work at the site where methylene chloride is
repackaged, but who do not directly perform the repackaging activity. ONUs for repackaging
include supervisors, managers, and tradesmen that may be in the repackaging area but do not
perform tasks that result in the same level of exposures as repackaging workers.
Since ONUs do not directly handle formulations containing methylene chloride, EPA expects
ONU inhalation exposures to be lower than worker inhalation exposures. Information on
processes and worker activities are insufficient to determine the proximity of ONUs to workers
and sources of emissions, so relative exposure of ONUs to workers cannot be quantified.
Table 2-38 presents modeled dermal exposures during repackaging.
Table 2-38. Summary of Dermal Exposure Doses to Methylene Chloride for Repackaging
Occupational
Kxposurc
Scenario
I se Setting
(Industrial vs.
Commercial)
.Maximum
Weight
Traction.
^ iIitih'1
Dermal Kx|
(mg/
Central
Tendency
)osurc Dose
.lav)1'
High KihI
Calculated
Traction
Absorbed.
r iiiiN
Repackaging
Industrial
1.0
60
180
0.08
a - EPA assumes repackaging of methylene chloride at 100% concentration.
b - Conditions where no gloves are used, or for any glove / gauntlet use without permeation data and without
employee training (PF = 1).
Potential impacts of PFs are presented as what-if scenarios in the dermal exposure summary Table 2-85.
In summary, dermal and inhalation exposures are expected for this scenario. EPA has described
uncertainties for this scenario in Section 4.4.2.
Page 140 of 753

-------
EPA considered the assessment approach, the quality of the data, and uncertainties in assessment
results to determine a level of confidence for the 8-hr TWA data. For the inhalation air
concentration data, the primary strengths include the assessment approach, which is the use of
monitoring data, the highest of the inhalation approach hierarchy. These monitoring data include
5 data points from 1 source, and the data quality ratings from systematic review for these data
were medium. The primary limitations of these data include the age of the data (pre-PEL rule)
and uncertainty of the representativeness of these data toward the true distribution of inhalation
concentrations for the industries and sites covered by this scenario. No data were available to
compare pre- and post-PEL rule exposures in Section 2.4.1.1. Based on these strengths and
limitations of the inhalation air concentration data, the overall confidence for these 8-hr TWA
data in this scenario is medium to low. The overall confidence of the dermal dose results is
medium (full discussion in Section 2.4.1.3).
2.4.1.2.5 Batch Open-Top Vapor Decreasing
EPA found no monitoring data for methylene chloride in this use. To fill this data gap, EPA
performed modeling of near-field and far-field exposure concentrations in the OTVD scenario
for both workers and ONUs. Modeling details are in Appendix F of the supplemental document
titled "Risk Evaluation for Methylene Chloride (Dichlorome thane, DCM) CASRN: 75-09-2,
Supplemental Information on Releases and Occupational Exposure Assessment" (EPA, 2019b).
The central tendency and high-end 8-hr TWA exposure concentrations for this scenario exceed
the OSHA PEL value of 87 mg/m3 (25 ppm) as an 8-hr TWA.
Estimates of ADC and LADC for use in assessing risk were made using the approach and
equations described in Section 2.4.1.1 and are presented in Table 2-39.
Table 2-39. Statistical Summary of Methylene Chloride 8-hr TWA Exposures (ADC and
LADC) for Workers and ONUs for Batch Open-Top Vapor Degreasing	



Data Quality



Rating of



Associated Air

Central Tendency
lligh-lnd
Concentration

(nig/m5)
(mg/nr')
Data
Workers (Near-Field)
8-hr TWA Exposure Concentration
170
740

Average Daily Concentration
(ADC)
38
170
N/A - Modeled
Data
Lifetime Average Daily
Concentration (LADC)
67
380
ONUs (Far-Field)
8-hr TWA Exposure Concentration
86
460

Average Daily Concentration
(ADC)
20
100
N/A - Modeled
Data
Lifetime Average Daily
Concentration (LADC)
34
230
Page 141 of 753

-------
Table 2-40 presents modeled dermal exposures during batch open-top vapor degreasing use.
Table 2-40. Summary of Dermal Exposure Doses to Methylene Chloride for Batch Open-
Top Vapor Degreasing	
Occupational
Kxposure
Scenario
I se Selling
(Industrial vs.
Com in ercial)
Maximum
Weight
Traction.
^ iIitih'1
Dermal K\|
(mg/
Central
Tendency
)osurc Dose
.lay)1'
High KihI
Calculated
Traction
Absorbed.
r iiiiN
Batch Open-Top
Vapor
Degreasing
Industrial
1.0
60
180
0.08
a - EPA assumes that 100% methylene chloride is used for vapor degreasing operations,
b - Conditions where no gloves are used, or for any glove / gauntlet use without permeation data and without
employee training (PF = 1).
Potential impacts of PFs are presented as what-if scenarios in the dermal exposure summary Table 2-85.
In summary, dermal and inhalation exposures are expected for this scenario. EPA has described
uncertainties for this scenario in Section 4.4.2.
EPA considered the assessment approach, the quality of the data, and uncertainties in assessment
results to determine a level of confidence for the 8-hr TWA inhalation air concentrations. The
primary strengths include the assessment approach, which is the use of modeling, in the middle
of the inhalation approach hierarchy. A Monte Carlo simulation using the Latin hypercube
sampling method with 100,000 iterations was used to capture the range of potential input
parameters. Vapor generation rates were derived from methylene chloride unit emissions and
operating hours reported in the 2014 NEI (EPA. 2018a). The primary limitations of the air
concentration outputs from the model include the uncertainty of the representativeness of these
data toward the true distribution of inhalation concentrations for the industries and sites covered
by this scenario. Added uncertainties include that emissions data available in the 2014 NEI were
only found for eight total units, and the underlying methodologies used to estimate these
emissions are unknown. Based on these strengths and limitations of the air concentrations, the
overall confidence for these 8-hr TWA data in this scenario is medium to low. The overall
confidence of the dermal dose results is medium (full discussion in Section 2.4.1.3).
2.4.1.2.6 Conveyorized Vapor Degreasing
EPA found no monitoring data for methylene chloride in this use. To fill this data gap, EPA
performed modeling of near-field and far-field exposure concentrations in the conveyorized
vapor degreasing scenario for both workers and ONUs. Modeling details are in Appendix F of
the supplemental document titled " Risk Evaluation for Methylene Chloride (Dichloromethane,
DCM) CASRN: 75-09-2, Supplemental Information on Releases and Occupational Exposure
Assessment"(EPA.., 2019b). The central tendency 8-hr TWA worker exposure concentration for
this scenario is approximately twice the OSHA PEL value of 87 mg/m3 (25 ppm) as an 8-hr
TWA, while the high-end estimate is approximately five times higher. Exposure concentrations
for ONUs are also considerably higher than the OSHA PEL.
Page 142 of 753

-------
Estimates of ADC and LADC for use in assessing risk were made using the approach and
equations described in Section 2.4.1.1 and are presented in Table 2-41.
Table 2-41. Statistical Summary of Methylene Chloride 8-hr TWA Exposures (ADC and
LADC) for Workers and ONUs for Conveyorized Vapor Degreasing	

Central Tendency
(nig/nr*)
lligh-lnd
(ing/nr*)
Dala Quality
Rating of
Associated Air
Concentration
Dala
Workers (Near-Field)
8-hr TWA Exposure
Concentration
490
1,400
N/A - Modeled
Data
Average Daily Concentration
(ADC)
110
320
Lifetime Average Daily
Concentration (LADC)
190
720
ONUs (Far-Field)
8-hr TWA Exposure
Concentration
250
900
N/A - Modeled
Data
Average Daily Concentration
(ADC)
58
210
Lifetime Average Daily
Concentration (LADC)
100
460
Table 2-42 presents modeled dermal exposures during conveyorized vapor degreasing use.
Table 2-42. Summary of Dermal Exposure Doses to Methylene Chloride for Conveyorized
Vapor Degreasing	
Occupational
Kxposure
Scenario
I se Setting
(Industrial vs.
Commercial)
.Maximum
Weight
Traction.
^ iIitih'1
Dermal K\|
(mg/
Central
Tendency
)osurc Dose
.lay)1'
High KihI
Calculated
Traction
Absorbed.
r iiiiN
Conveyorized
Vapor
Degreasing
Industrial
1.0
60
180
0.08
a - EPA assumes that 100% methylene chloride is used for vapor degreasing operations,
b - Conditions where no gloves are used, or for any glove / gauntlet use without permeation data and without
employee training (PF = 1).
Potential impacts of PFs are presented as what-if scenarios in the dermal exposure summary Table 2-85.
In summary, dermal and inhalation exposures are expected for this scenario. EPA has described
uncertainties for this scenario in Section 4.4.2.
Page 143 of 753

-------
EPA considered the assessment approach, the quality of the data, and uncertainties in assessment
results to determine a level of confidence for the 8-hr TWA inhalation air concentrations. The
primary strengths include the assessment approach, which is the use of modeling, in the middle
of the inhalation approach hierarchy. A Monte Carlo simulation using the Latin hypercube
sampling method with 100,000 iterations was used to capture the range of potential input
parameters. Vapor generation rates were derived from methylene chloride unit emissions and
operating hours reported in the 2014 NEI (	). The primary limitations of the air
concentration outputs from the model include the uncertainty of the representativeness of these
data toward the true distribution of inhalation concentrations for the industries and sites covered
by this scenario. Added uncertainties include that emissions data available in the 2014 NEI were
only found for two total units, and the underlying methodologies used to estimate these
emissions are unknown. Based on these strengths and limitations of the air concentrations, the
overall confidence for these 8-hr TWA data in this scenario is medium to low. The overall
confidence of the dermal dose results is medium (full discussion in Section 2.4.1.3).
2.4.1.2.7 Cold Cleaning
EPA found limited inhalation monitoring data for cold cleaning manufacturing from published
literature sources. TNO (CIVO) (1999) indicated that mean exposure values for cold degreasing
were found to be approximately 280 mg/m3 on average, ranging from 14 to over 1,000 mg/m3.
The referenced data were from United Kingdom (U.K.) Health and Safety Executive (HSE)
reports from 1998, but details, including specific worker activities and sampling times were not
available. Lists of all inhalation monitoring data found in data sources and associated systematic
review data quality ratings are available in Appendix A of the supplemental document "Risk
Evaluation for Methylene Chloride (Dichlorome thane, DCM) CASRN: 75-09-2, Supplemental
Information on Releases and Occupational Exposure Assessment" (EPA. 2019 b).
Because the underlying data were not available, EPA assessed the average value of 280 mg/m3 as
the central tendency, and the maximum reported value of 1,000 mg/m3 as the high-end estimate
of potential occupational inhalation exposure for this scenario. The central tendency 8-hr TWA
exposure concentration for this scenario is approximately three times the OSHA PEL value of
87 mg/m3 (25 ppm) as an 8-hr TWA, while the high-end estimate is almost 12 times higher. All
data points were pre-PEL rule or during the transition period (see Section 2.4.1.1 for pre-PEL,
transition, and post-PEL rule periods).
Using these 8-hr TWA exposure concentrations, EPA calculated the ADC and LADC. The
results of these calculations are shown in Table 2-43.
Page 144 of 753

-------
Table 2-43. Worker Exposure to Methylene C
lloride During
Cold Cleaning3




Data Quality




Rating of

N il in her
(en (nil

Associated Air

of
Tendency
11 igh-lnd
Concentration

Samples
(in /nr')
(mg/nr')
Data
8-hr TWA Exposure
Concentration

280
1,000

Average Daily Concentration
(ADC)
unknownb
64
230
Low
Lifetime Average Daily
Concentration (LADC)

110
510

Source: TNO (CIVO) (.1.999)
a - No data for ONUs were found; EPA assumes that ONU exposures are less than worker exposures,
b - One source provided a range of values for an unknown number of samples.
EPA has not identified short-term exposure data from cold cleaning using methylene chloride,
nor personal or area data on or parameters for modeling potential ONU inhalation exposures.
Since ONUs do not directly handle formulations containing methylene chloride, EPA expects
ONU inhalation exposures to be lower than worker inhalation exposures. Information on
processes and worker activities are insufficient to determine the proximity of ONUs to workers
and sources of emissions, so relative exposure of ONUs to workers cannot be quantified.
Note that EPA also performed a Monte Carlo simulation with 100,000 iterations using the Latin
hypercube sampling method to model near-field and far-field exposure concentrations for the
cold cleaning scenario. EPA calculated the 50th and 95th percentile 8-hr TWA concentrations to
represent a central tendency and worst-case estimate of potential occupational inhalation
exposures, respectively, for this life cycle stage. For workers, the modeled 8-hr TWA exposures
are 1 mg/m3 at the 50th percentile and 103.8 mg/m3 at the 95th percentile. For ONUs, the modeled
8-hr TWA exposures are 0.5 mg/m3 at the 50th percentile and 60 mg/m3 at the 95th percentile. For
the risk evaluation, EPA used the available monitoring data for several reasons. The monitoring
data have higher weight of evidence due to higher relevance than modeling results for this use
for several reasons because the monitoring data are known to be relevant to this use, and the
modeled results cannot be validated and do not capture the full range of possible exposure
concentrations identified by the monitoring data for this use. For example, the 95th percentile
modeling results appear equal to about the 25th percentile of monitoring data. Modeling details
are in Appendix F of the supplemental document titled "Risk Evaluation for Methylene Chloride
(Dichloromethane, DCM) CASRN: 75-09-2, Supplemental Information on Releases and
Occupational Exposure Assessment" CEP A. 2019b).
Table 2-44 presents modeled dermal exposures during cold cleaning use.
Page 145 of 753

-------
Table 2-44. Summary of Dermal Exposure Doses to Methylene Chloride for Cold Cleaning
Occupational
Kxposure
Scenario
I se Setting
(Industrial vs.
Commercial)
Maximum
Weight
l-'raction.
^ ilei in'1
Dermal K\|
(mg/
Central
Tendency
)osurc Dose
.lay)1'
High I nd
Calculated
l-'raction
Absorbed.
r iiiiN
Cold Cleaning
Industrial
1.0
60
180
0.08
a - EPA assumes that 100% methylene chloride is used for cold cleaning operations.
b - Conditions where no gloves are used, or for any glove / gauntlet use without permeation data and without
employee training (PF = 1).
Potential impacts of PFs are presented as what-if scenarios in the dermal exposure summary Table 2-85.
In summary, dermal and inhalation exposures are expected for this scenario. EPA has described
uncertainties for this scenario in Section 4.4.2.
EPA considered the assessment approach, the quality of the data, and uncertainties in assessment
results to determine a level of confidence for the 8-hr TWA data. For the inhalation air
concentration data, the primary strengths include the assessment approach, which is the use of
monitoring data, the highest of the inhalation approach hierarchy. These monitoring data include
3 data points from 1 source, and the data quality ratings from systematic review for these data
were low. The primary limitations of these data include the age of the data (pre-PEL rule and
transition period) and uncertainty of the representativeness of these data toward the true
distribution of inhalation concentrations for the industries and sites covered by this scenario. The
analysis of pre- and post-rule OSHA data (summarized in Table 2-26) did not have enough data
to compare pre- to post-rule mean exposure concentrations for this OES. Additionally, the source
reported data from two studies, one of which was presented as a range, and the other presented as
a high-end exposure if stringent controls are applied. No data were available to compare pre- and
post-PEL rule exposures in Section 2.4.1.1. Based on these strengths and limitations of the
inhalation air concentration data, the overall confidence for these 8-hr TWA data in this scenario
is medium to low. The overall confidence of the dermal dose results is medium (full discussion
in Section 2.4.1.3).
2.4.1.2.8 Commercial Aerosol Products (Aerosol Degreasing, Aerosol
Lubricants, Automotive Care Products)
EPA found limited inhalation monitoring data from a published literature source and associated
the data with commercial aerosol product applications. Finkel (201?) submitted workplace
monitoring data obtained from a FOIA request of OSHA. EPA extracted relevant monitoring
data by crosswalking the Standard Industrial Classification (SIC) codes in the dataset with
potentially relevant NAICS codes as discussed in the supplemental document"Risk Evaluation
for Methylene Chloride (Dichloromethane, DCM) CASRN: 75-09-2, Supplemental Information
on Releases and Occupational Exposure Assessment" (EPA. 2019b).
For the set of 21 data points, 8-hr TWA exposure concentrations ranged from 0.1 to 396.5
mg/m3. Worker activity information was not available; therefore, it was not possible to
specifically attribute the exposures to aerosol product applications, nor to distinguish workers
from ONUs. While additional activities are possible at these sites, such as application of paints
Page 146 of 753

-------
and coatings, use of adhesives, and use of paint strippers that contributed to methylene chloride
exposures, EPA assumes that exposures are representative of worker exposures during aerosol
product application. Sample times also varied; EPA assumed that any measurement longer than
15 minutes was done to assess compliance with the 8-hr TWA PEL, as opposed to the 15-minute
STEL, and averaged all applicable data points over 8 hours.
The central tendency 8-hr TWA exposure concentration is more than an order of magnitude
lower than the OSHA PEL value of 87 mg/m3 (25 ppm), while the high-end 8-hr TWA exposure
concentrations for this scenario is approximately 3 times the OSHA PEL. Of the 21 data points,
7 of the data points were pre-PEL rule, while 13 data points were post-PEL rule (see Section
2.4.1.1 for pre-PEL, transition, and post-PEL rule periods).
Using these 8-hr TWA exposure concentrations, EPA calculated the ADC and LADC. The
results of these calculations are shown in Table 2-47.
Table 2-45. Worker Exposure to Methylene Chloride During Aerosol Product Applications
Based on Monitoring Data"					




Data Qualify




Rating of

N il in her
Central

Associated Air

of
Tendency
Iligh-Knd
Concentration

Samples
(nig/m')
(ing/nr*)
Data
8-hr TWA Exposure
Concentration

6.0
230

Average Daily Concentration
(ADC)
21
1.4
52
Medium
Lifetime Average Daily
Concentration (LADC)

2.4
120

Source: Finket (20.1.7)
a - No data for ONUs were found; EPA assumes that ONU exposures are less than worker exposures.
EPA has not identified short-term exposure data from aerosol degreasing using methylene
chloride, nor personal or area data on or parameters for modeling potential ONU inhalation
exposures. Since ONUs do not directly handle formulations containing methylene chloride, EPA
expects ONU inhalation exposures to be lower than worker inhalation exposures. Information on
processes and worker activities are insufficient to determine the proximity of ONUs to workers
and sources of emissions, so relative exposure of ONUs to workers cannot be quantified.
EPA also performed modeling for near-field and far-field exposure concentrations for the aerosol
degreasing for both workers and ONUs. Modeling details are in Appendix F of the supplemental
document titled " Risk Evaluation for Methylene Chloride (Dichloromethane, DCM) CASRN: 75-
09-2, Supplemental Information on Releases and Occupational Exposure Assessment" (EPA.
2019b). Both the central tendency and high-end 8-hr TWA exposure concentrations for workers
in this this scenario are lower than the OSHA PEL value of 87 mg/m3 (25 ppm) as an 8-hr TWA.
ONUs include employees that work at the facility but do not directly apply the aerosol product to
Page 147 of 753

-------
the service item and are therefore expected to have lower inhalation exposures and are not
expected to have dermal exposures. ONU exposures are an order of magnitude lower than the
worker exposures.
Estimates of ADC and LADC for use in assessing risk were made using the approach and
equations described in the Section 2.4.1.1 and are presented in Table 2-46. EPA also modeled
maximum 1-hr TWA exposures, which are also shown in the table.
Table 2-46. Statistical Summary of Methylene Chloride 8-hr and 1-hr TWA Exposures
ADC and LADC) for Workers and ONUs for Aerosol Products Based on Modeling

Central

Data Quality Killing

Tendency
Iligh-Knd
of Associated Air

(ing/nr*)
(in /nr')
Concentration Data
Workers (Near-Field)
8-hr TWA Exposure Concentration
22
79

Average Daily Concentration
(ADC)
5.0
18
N/A - Modeled Data
Lifetime Average Daily
Concentration (LADC)
8.7
40
Maximum 1-hr TWA Exposures
68
230

ONUs (Far-Field)
8-hr TWA Exposure Concentration
0.40
3.3

Average Daily Concentration
(ADC)
0.09
0.74
N/A - Modeled Data
Lifetime Average Daily
Concentration (LADC)
0.16
1.7
Maximum 1-hr TWA Exposures
1.2
9.7

Table 2-47 presents modeled dermal exposures during commercial aerosol use.
Table 2-47. Summary of Dermal Exposure Doses to Methylene Chloride for Commercial
Aerosol Product Uses
Occupational
Kxposurc
Scenario
I se Setting
(Industrial vs.
Commercial)
.Maximum
Weight
Traction.
^ iIitih'1
Dermal K\|
(mg/
Central
Tendency
)osurc Dose
.lay)1'
High KihI
Calculated
Traction
Absorbed.
r iiiiN
Commercial
Aerosol Product
Uses
Commercial
1.0
94
280
0.13
a - EPA assumes that 100% methylene chloride is used for commercial aerosol product uses,
b - Conditions where no gloves are used, or for any glove / gauntlet use without permeation data and without
employee training (PF = 1).
Potential impacts of PFs are presented as what-if scenarios in the dermal exposure summary Table 2-85.
Page 148 of 753

-------
In summary, dermal and inhalation exposures are expected for this scenario. EPA has described
uncertainties for this scenario in Section 4.4.2.
EPA considered the assessment approach, the quality of the data, and uncertainties in assessment
results to determine a level of confidence for the 8-hr TWA data.
For the inhalation air monitoring concentration data, the primary strengths include the
assessment approach, which is the use of monitoring data, the highest of the inhalation approach
hierarchy. These monitoring data include 21 data points from 1 source, and the data quality
ratings from systematic review for these data were medium. The primary limitations of these
data include the age of the data (7 data points pre-PEL rule and 13 data points post-PEL rule) and
uncertainty of the representativeness of these data toward the true distribution of inhalation
concentrations for the industries and sites covered by this scenario. As discussed earlier in this
section, key metadata such as worker activity and sampling descriptions were not available to
specifically attribute exposures to aerosol degreasing or to determine whether sampled activities
were representative of full-shift exposures. A comparison of pre- and post-rule OSHA data
(summarized in Table 2-26) shows that mean exposure concentrations increased by 129.7% from
pre- to post-rule. Based on these strengths and limitations of the non-spray inhalation air
concentration data, the overall confidence for these 8-hr TWA data in this scenario is medium to
low.
For the modeling approach, the primary strengths include the assessment approach, which is the
use of modeling, in the middle of the inhalation approach hierarchy. A Monte Carlo simulation
using the Latin hypercube sampling method with 100,000 iterations was used to capture the
range of potential input parameters. Various model parameters were derived from a California
Air Resources Board (CARB) brake service study at 137 automotive maintenance and repair
shops in California. The primary limitations of the air concentration outputs from the model
include the uncertainty of the representativeness of these brake servicing data toward the true
distribution of inhalation concentrations for the industries and sites covered by this scenario.
Based on these strengths and limitations of the air concentrations, the overall confidence for
these 8-hr TWA model results in this scenario is medium to low. The overall confidence of the
dermal dose results is medium (full discussion in Section 2.4.1.3).
2.4.1.2.9 Adhesives and Sealants
EPA found inhalation exposure data for both spray and non-spray industrial adhesive
application, as well as data for unknown application methods. 8-hr TWA data are primarily from
Finkel (2017) who submitted workplace monitoring data obtained from a FOIA request of
OSHA. EPA extracted relevant monitoring data by crosswalking the Standard Industrial
Classification (SIC) codes in the dataset with potentially relevant NAICS codes as discussed in
the supplemental document" Risk Evaluation for Methylene Chloride (Dichloromethane, DCM)
CASRN: 75-09-2, Supplemental Information on Releases and Occupational Exposure
Assessment"(EPA, 2019b). For the set of 468 data points, 8-hr TWA exposure concentrations
ranged from 0.11 to 2,280 mg/m3. Worker activity information was not available; therefore, it
was not possible to specifically attribute the exposures to application of adhesives and sealants,
nor to distinguish workers from ONUs. While additional activities are possible at these sites,
such as application of paints and coatings and use of paint strippers that contribute to methylene
Page 149 of 753

-------
chloride exposures, EPA assumes that exposures are representative of worker exposures during
use of adhesives and sealants. Sample times also varied; EPA assumed that any measurement
longer than 15 minutes was done to assess compliance with the 8-hr TWA PEL, as opposed to
the 15-minute STEL, and averaged all applicable data points over 8 hours. Additional 8-hr TWA
data for non-spray uses are primarily from a 1985 EPA Risk Assessment that compiled
laminating and gluing activities in various industries, ranging from ND to 575 mg/m3 (97
samples) (EPA. 1985). A 1984 National Institute for Occupational Safety and Health (NIOSH)
Health Hazard Evaluation (HHE) performed at a flexible circuit board manufacturing site
encompassed various worker activities in adhesive mixing and laminating areas, ranging from
86.8 to 458.5 mg/m3 (12 samples) CHIOS 5). 8-hr TWA data for spray uses are available
from three sources TN( ^ i 1 O) s )9); \\ U \ I 96b); n> \ j 85). Lists of all inhalation
monitoring data found in data sources and associated systematic review data quality ratings are
available in Appendix A of the supplemental document" Risk Evaluation for Methylene Chloride
(Dichloromethane, DCM) CASRN: 75-09-2, Supplemental Information on Releases and
Occupational Exposure Assessment" CEP A. 2019b).
Considering 8-hr TWA samples, 100 personal monitoring samples were available for industrial
non-spray adhesives use, 16 personal monitoring samples were available for industrial spray
adhesives use, while 468 personal monitoring samples were available for unknown application
methods. EPA calculated the 50th and 95th percentile 8-hr TWA concentrations to represent a
central tendency and high-end estimate of potential occupational inhalation exposures,
respectively, for this scenario. Central tendency 8-hr TWA exposure concentrations for these
scenarios are less than half of the OSHA PEL value of 87 mg/m3 (25 ppm) as an 8-hr TWA,
while high-end estimates are between three and eight times the OSHA PEL. For non-spray
application, 98 of the data points were pre-PEL rule, while 2 data points were post-PEL rule. For
spray application all 16 data points were from the pre-PEL or transition period (see Section
2.4.1.1 for pre-PEL, transition, and post-PEL rule periods). For unknown application methods,
222 of the data points were pre-PEL rule, 49 were during the transition period, while 197 data
points were post-PEL rule.
Using these 8-hr TWA exposure concentrations, EPA calculated the ADC and LADC as
described in Section 2.4.1.1. The results of these calculations are shown in Table 2-48, Table
2-49, and Table 2-50 for industrial non-spray, industrial spray, and unknown adhesives
application, respectively.
Page 150 of 753

-------
Table 2-48. Worker Exposure to Methylene Chloride During Industrial Non-Spray
Adhesives Use3

Nu in her of
Samples
Central
Tendency
(ing/nr*)
Iligh-Knd
(ing/nr*)
Data Qualify Ualing
ol" Associated Air
Concentration Data
S-hr TWA Exposure Concentration
100
10
300
High
Average Daily Concentration
(ADC)
2.4
67
Lifetime Average Daily
Concentration (LADC)
4.2
150
Sources: NIOSH (.1.985): EPA (1.985): OSHA (20.1.9)
a - No data for ONUs were found; EPA assumes that ONU exposures are less than worker exposures.
Table 2-49. Worker Exposure to Methylene Chloride During Industrial Spray Adhesives
Usea


Central

Data Quality Ualing

Number ol'
Tendency
Iligh-Knd
ol'Associated Air

Samples
(nig/nr*)
(ing/nr*)
Concentration Data
8-hr TWA Exposure
Concentration

39
560

Average Daily Concentration
(ADC)
16
8.9
130
Low to High
Lifetime Average Daily
Concentration (LADC)

16
290

Sources: TNO (CIVO) (.1.999): WHO (1996b): EPA C!'>85)
a - No data for ONUs were found; EPA assumes that ONU exposures are less than worker exposures.
Table 2-50. Worker Exposure to Methylene Chloride During Adhesives and Sealants Use
(Unknown Application Method)11


Central

Data Quality Ualing

.Number ol'
Tendency
Iligh-Knd
ol'Associated Air

Samples
(ing/nr*)
(nig/nr*)
Concentration Data
8-hr TWA Exposure
Concentration

27
690

Average Daily Concentration
(ADC)
468
6.2
160
Medium
Lifetime Average Daily
Concentration (LADC)

11
350

Sources: Finket (20.1.7)
a - No data for ONUs were found; EPA assumes that ONU exposures are less than worker exposures.
Table 2-51 summarizes available short-term exposure data available from the same references
and industries identified above for the 8-hr TWA data, as well as OSHA inspection data. Data
range from 12 mg/m3to 720 mg/m3 during adhesive application.
Page 151 of 753

-------
Table 2-51. Summary of Personal Short-Term Exposure Data for Methylene Chloride
During Industrial Adhesives Use 				
Occupiitioiiiil
Kxposure
Scenario
Source
Worker
Acli\ it v
Methylene
Chloride Short-
Term
Concentriition
(ni/nr()
Kxposure
Diimtion
(mill)
l)il;i Qiiiility
killing ol'
Associated Air
Concentriition
l):it:i
Unknown
OSHA (2019)
Adhesive
Sprayer
720
580
140
480
160
360
100
280
12
15 3
High
Flexible Circuit
Board
Manufacturing
NlfWH (I C)8
-------
Table 2-52. Summary of Dermal Exposure Doses to Methylene Chloride for Adhesives and
Sealants Uses
Occupational
Kxposure
Scenario
I se Sell in
(Industrial vs.
Com in ercial)
.Maximum
Weight
Traction.
^ iIitih'1
Dermal K\|
(m/
Central
Tendency
)osurc Dose
.lay)1'
High KihI
Calculated
Traction
Absorbed.
r iiiiN
Adhesives and
Sealants Uses
Industrial
1.0
60
180
0.08
a - The 2017 Preliminary Use Document (U.S. EPA. 2017b) and EPA's Use and Market Profile for Methylene
Chloride (U.S. EPA. 2017g) list commercial products containing between 30 and 100% methylene chloride,
b - Conditions where no gloves are used, or for any glove / gauntlet use without permeation data and without
employee training (PF = 1).
Potential impacts of protection factors are presented as what-if scenarios in the dermal exposure summary Table
2-85.
In summary, dermal and inhalation exposures are expected for this scenario. EPA has described
uncertainties for this scenario in Section 4.4.2.
EPA considered the assessment approach, the quality of the data, and uncertainties in assessment
results to determine a level of confidence for the 8-hr TWA data. For the non-spray inhalation air
concentration data, the primary strengths include the assessment approach, which is the use of
monitoring data, the highest of the inhalation approach hierarchy. These monitoring data include
100 data points from 3 sources, and the data quality ratings from systematic review for these data
were high. The primary limitations of these data include the age of the data (98 data points pre-
PEL rule and 2 data points post-PEL rule) and uncertainty of the representativeness of these data
toward the true distribution of inhalation concentrations for the industries and sites covered by
this scenario. A comparison of pre- and post-rule OSHA data (summarized in Table 2-26) shows
that mean exposure concentrations decreased by 45.5% from pre- to post-rule. Based on these
strengths and limitations of the non-spray inhalation air concentration data, the overall
confidence for these 8-hr TWA data in this scenario is medium.
For the spray inhalation air concentration data, the primary strengths include the assessment
approach, which is the use of monitoring data, the highest of the approach hierarchy. These
monitoring data include 16 data points from 3 sources, and the data quality ratings from
systematic review for these data were low to high. The primary limitations of these data include
the age of the data (all data points were from the pre-PEL or transition period) and uncertainty of
the representativeness of these data toward the true distribution of inhalation concentrations for
the industries and sites covered by this scenario. A comparison of pre- and post-rule OSHA data
(summarized in Table 2-26) shows that mean exposure concentrations decreased by 45.5% from
pre- to post-rule. Based on these strengths and limitations of the spray inhalation air
concentration data, the overall confidence for these 8-hr TWA data in this scenario is medium to
low. The overall confidence of the dermal dose results is medium (full discussion in Section
2.4.1.3).
For the unknown application inhalation air concentration data, the primary strengths include the
assessment approach, which is the use of monitoring data, the highest of the approach hierarchy.
Page 153 of 753

-------
These monitoring data include 468 data points from 1 source, and the data quality ratings from
systematic review for these data were medium. The primary limitations of these data include the
age of the data (222 of the data points were pre-PEL rule, 49 were during the transition period,
while 197 data points were post-PEL rule) and uncertainty of the representativeness of these data
toward the true distribution of inhalation concentrations for the industries and sites covered by
this scenario. As discussed earlier in this section, key metadata such as worker activity and
sampling descriptions were not available to specifically attribute exposures to use of adhesives
and sealants or to determine whether sampled activities were representative of full-shift
exposures. A comparison of pre- and post-rule OSHA data (summarized in Table 2-26) shows
that mean exposure concentrations decreased by 45.5% from pre- to post-rule. Based on these
strengths and limitations of the spray inhalation air concentration data, the overall confidence for
these 8-hr TWA data in this scenario is low. The overall confidence of the dermal dose results is
medium (full discussion in Section 2.4.1.3).
2.4.1.2.10 Paints and Coatings
Occupational exposures for use of paints and coatings containing methylene chloride are
described in this section. Occupational exposures for methylene chloride-based paint and coating
removers were assessed in EPA's TSCA Work Plan Chemical Risk Assessment Methylene
Chloride: Paint Stripping Use (	), and those results are included in Appendix L.
Lists of all inhalation monitoring data found in data sources and associated systematic review
data quality ratings are available in Appendix A of the supplemental document"Risk Evaluation
for Methylene Chloride (Dichloromethane, DCM) CASRN: 75-09-2, Supplemental Information
on Releases and Occupational Exposure Assessment" (	2).
EPA found 8-hr TWA spray coating data primarily from monitoring data at various facility
types, such as sporting goods stores, metal products, air conditioning equipment, etc., as
compiled in the 1985 EPA assessment, ranging from ND to 439.7 mg/m3 (25 data points) (EPA.
1985). Two additional spray-painting data points were available from OSHA inspections
between 2012 and 2016, one in the general automotive repair sector, and the other in the Wood
Kitchen Cabinet and Countertop Manufacturing sector, of 14.2 and 222.3 mg/m3 (OSHA. 2019).
For unknown coating methods, Finkel (2017) submitted workplace monitoring data obtained
from a FOIA request of OSHA. EPA extracted relevant monitoring data by crosswalking the
Standard Industrial Classification (SIC) codes in the dataset with the NAICS codes as discussed
in the supplemental document" Risk Evaluation for Methylene Chloride (Dichloromethane,
DCM) CASRN: 75-09-2, Supplemental Information on Releases and Occupational Exposure
Assessment"(EPA. 2019b). For the set of 266 data points, 8-hr TWA exposure concentrations
ranged from 0.11 to 3,365 mg/m3. Worker activity information was not available; therefore it
was not possible to specifically attribute the exposures to the use of paints and coatings, nor to
distinguish workers from ONUs. While additional activities are possible at these sites, such as
use of paint strippers that contribute to methylene chloride exposures, EPA assumes that
exposures are representative of worker exposures during use of paints and coatings. Sample
times also varied; EPA assumed that any measurement longer than 15 minutes was done to
assess compliance with the 8-hr TWA PEL, as opposed to the 15-minute STEL, and averaged all
applicable data points over 8 hours. Additional discussion of data treatment is included in
Appendix H. The U.S. Department of Defense (DoD) provided five monitoring data points from
painting operations during structural repair. The worker activities did not indicate the method of
Page 154 of 753

-------
paint application. The activities were also stated to have low durations (<15 minutes) but
provided sampling data that occurred over 2-hr periods. EPA assumed that there was no
exposure to methylene chloride over the remainder of the shift and calculated 8-hr TWA
exposures; this assumption may not capture the entire exposure scenario, and the calculated
result is the minimum exposure during the shift.
Because the method of paint application is unknown, EPA presents the spray application data
and the unknown application data separately.
For spray painting/coating operations, 27 personal monitoring data samples were available; EPA
calculated the 50th and 95th percentile 8-hr TWA concentrations to represent a central tendency
and high-end estimate of potential occupational inhalation exposures, respectively, for this
scenario. The central tendency 8-hr TWA exposure concentration for this scenario is below the
OSHA PEL value of 87 mg/m3 (25 ppm) as an 8-hr TWA, but the high-end estimate is
approximately four times higher. Of the 27 data points, 25 were pre-PEL rule, while 2 were post-
PEL rule (see Section 2.4.1.1 for pre-PEL, transition, and post-PEL rule periods).
For unknown application method operations, 271 data points were available. EPA calculated the
50th and 95th percentile 8-hr TWA concentrations to represent a central tendency and high-end
estimate of potential occupational inhalation exposures, respectively, for this scenario. The
central tendency 8-hr TWA exposure concentration for this scenario is approximately seven
times below the OSHA PEL value of 87 mg/m3 (25 ppm) as an 8-hr TWA, and the high-end
estimate is approximately three times higher. Of the 271 data points, 72 were pre-PEL rule, 49
during the transition period, and 150 were post-PEL rule (see Section 2.4.1.1 for pre-PEL,
transition, and post-PEL rule periods).
Using these 8-hr TWA exposure concentrations, EPA calculated the ADC and LADC as
described in the Section 2.4.1.1. The results of these calculations are shown in Table 2-53 and
Table 2-54 for spray coating and unknown paint/coating application, respectively.
Table 2-53. Worker Exposure to Methylene Chloride During Paint/Coating Spray
Application3	

N il in her
of
Samples
Central
Tendency
(ing/nr*)
Iligh-Knd
(ing/nr*)
Data Qualify Rating
of Associated Air
Concentration Data
8-hr TWA Exposure
Concentration
27
70
360
High
Average Daily Concentration
(ADC)
16
83
Lifetime Average Daily
Concentration (LADC)
28
190
Sources: OSHA (20.1.9): EPA (1.985)
a - No data for ONUs were found; EPA assumes that ONU exposures are less than worker exposures.
Page 155 of 753

-------
Table 2-54. Worker Exposure to Methylene Chloride During Paint/Coating Application
(Unknown Application Method)3	

N il in her
of
Samples
Central
Tendency
(ing/nr*)
Iligh-Knd
(ing/nr*)
Data Qualify Rating
of Associated Air
Concentration Data
8-hr TWA Exposure
Concentration
271
12
260
High and Medium
Average Daily Concentration
(ADC)
2.8
60
Lifetime Average Daily
Concentration (LADC)
4.9
130
Sources: Defense Occupational and Environmental Health Readiness System - Industrial Hygiene (DOEHRS-IH)
(20.1.8); Finket (20.1.7)
a - No data for ONUs were found; EPA assumes that ONU exposures are less than worker exposures.
Table 2-55 summarizes available short-term exposure data available from the DoD sampling
identified above for the 8-hr TWA data, as well as short-term exposure data during painting at a
Metro bus maintenance shop in 1981, and spray painting in a spray booth at a metal fabrication
plant in 1973.
Page 156 of 753

-------
Table 2-55. Summary of Personal Short-Term Exposure Data for Methylene Chloride
During Paint/Coating Use 				



Mcllnlcnc

Diilii Qu;ili(\



Chloride Short-

Killing ol
Occn p;il iiii;il


Term
I'lxpoMirc
Associiiled Air
l'l\|)OMIIV

\\ orker
( oiieeuli'iilion
Diimlion
( oiicoii 1 r;il ion
Sccn;irio
Source
Ac(i\ i(\
img/iiv')
(mill)
Diilii
Metro Bus
Love and Kern
(1981)
Painting
ND (<0.01)
40 b

Maintenance
Shop
Painting
ND (<0.01)
50 c
Medium



64
32b



Spray Painter in
Aisle No. 2
54
32b



63
27 b



(Front) Spray
Booth

Metal
Vandervort and
36
20a
Medium
Fabrication
Plant
Polakoff (1973)

74
29 b

Spray Painter in
1.0
18a



Aisle No. 1
(Rear) Spray
Booth
3.0
23 b



4.0
22 b



Painting
Operations
4.1




Painting
Operations
4.1




Painting
Operations
4.1




Painting
Operations
4.1



Defense
Occiroational and
Environmental
Health Readiness
Priming
Operations
5.2


Department of
Defense -
Painting and
IND-002-00
Chemical
cleaning multi
ops.
1.7
15a
High
Coating
Operations
Hygiene
(DOEHRS-IH)
(20.1.8)
IND-006-00
Coating
Operations,
Multiple
Operations
1.9




IND-006-00





Coating
Operations,
Multiple
Operations
1.9




NPS ECE





aerosol can
13.5




painting



Industrial Sign
Manufacturing
OSHA (20.1.9)
Floor Manager,
Painter
133.9
72 c
High
ND - not detected
a - EPA evaluated 11 samples, with durations ranging from 15 to 20 minutes, as 15-minute exposures,
b - EPA evaluated seven samples, with durations ranging from of 22 to 32 minutes, as 30-minute exposures.
Page 157 of 753

-------
c - EPA evaluated one sample, with duration of 50 minutes, as 1 -hr exposure.
Note: The OSHA Short-term exposure limit (STEL) is 433 mg/m3 as a 15-min TWA.
EPA has not identified personal or area data on or parameters for modeling potential ONU
inhalation exposures. Since ONUs do not directly handle formulations containing methylene
chloride, EPA expects ONU inhalation exposures to be lower than worker inhalation exposures.
Information on processes and worker activities are insufficient to determine the proximity of
ONUs to workers and sources of emissions, so relative exposure of ONUs to workers cannot be
quantified.
Table 2-56 presents modeled dermal exposures during paint and coatings uses.
Table 2-56. Summary of Dermal Exposure Doses to Methylene Chloride for Paint and
Coatings Uses	
Occupational
Kxposure
Scenario
I se Setting
(Industrial vs.
Commercial)
.Maximum
Weight
Traction.
^ iIitih'1
Dermal K\|
(mg/
Central
Tendency
)osurc Dose
.lay)1'
High KihI
Calculated
Traction
Absorbed.
r iiiiN
Paint and
Coatings
Industrial
1.0
60
180
0.08
a - The 2016 CDR includes a submission that reports >90% concentration during commercial and consumer use
(U.S. EPA. 20.1.6'). EPA assumes up to 100% concentration, and that similar concentrations will be used for
industrial paints and coatings.
b - Conditions where no gloves are used, or for any glove / gauntlet use without permeation data and without
employee training (PF = 1).
Potential impacts of protection factors are presented as what-if scenarios in the dermal exposure summary Table
2-85.
In summary, dermal and inhalation exposures are expected for this scenario. EPA has described
uncertainties for this scenario in Section 4.4.2.
EPA considered the assessment approach, the quality of the data, and uncertainties in assessment
results to determine a level of confidence for the 8-hr TWA inhalation data. For the spray
inhalation air concentration data, the primary strengths include the assessment approach, which
is the use of monitoring data, the highest of the inhalation approach hierarchy. These monitoring
data include 27 data points from 2 sources, and the data quality ratings from systematic review
for these data were high and medium. The primary limitations of these data include the age of the
data (25 data points pre-PEL rule and 2 data points post-PEL rule) and uncertainty of the
representativeness of these data toward the true distribution of inhalation concentrations for the
industries and sites covered by this scenario. A comparison of pre- and post-rule OSHA data
(summarized in Table 2-26) shows that mean exposure concentrations decreased by 47.8% from
pre- to post-rule. Based on these strengths and limitations of the inhalation air concentration data,
the overall confidence for these 8-hr TWA data in this scenario is medium.
For the unknown application method spray inhalation air concentration data, the primary
strengths include the assessment approach, which is the use of monitoring data, the highest of the
approach hierarchy. These monitoring data include 271 data points from two sources, and the
Page 158 of 753

-------
data quality ratings from systematic review for these data were medium and high. The primary
limitations of these data include the age of the data (72 data points pre-PEL rule, 49 data points
from the transition period, and 150 data points post-PEL rule) and uncertainty of the
representativeness of these data toward the true distribution of inhalation concentrations for the
industries and sites covered by this scenario. As discussed earlier in this section, key metadata
such as worker activity and sampling descriptions were not available to specifically attribute
exposures to the use of paints and coatings or to determine whether sampled activities were
representative of full-shift exposures. Based on these strengths and limitations of the spray
inhalation air concentration data, the overall confidence for these 8-hr TWA data in this scenario
is low. The overall confidence of the dermal dose results is medium (full discussion in Section
2.4.1.3).
2.4.1.2.11 Adhesive and Caulk Removers
EPA did not find specific industry information exposure data for adhesive and caulk removers.
Products listed in EPA's Use and Market Profile for Methylene Chloride (	)
indicate potential use in flooring adhesive removal. Based on expected worker activities, EPA
assumes that the use of adhesive and caulk removers is similar to paint stripping by professional
contractors, as discussed in the supplemental document titled " Risk Evaluation for Methylene
Chloride (Dichloromethane, DCM) CASRN: 75-09-2, Supplemental Information on Releases and
Occupational Exposure Assessment"(EP A, 2019b). Therefore, EPA uses the air concentration
data from the 2014 Risk Assessment on Paint Stripping Use for Methylene Chloride (U.S. EPA.
2014V
EPA calculated the 50th and 95th percentile 8-hr TWA concentrations to represent a central
tendency and high-end estimate of potential occupational inhalation exposures, respectively, for
this scenario. The central tendency 8-hr TWA exposure concentration for this scenario is
approximately 17 times the OSHA PEL value of 87 mg/m3 (25 ppm) as an 8-hr TWA, while the
high-end estimate is almost 34 times higher. All of the data points were pre-PEL rule.
Using these 8-hr TWA exposure concentrations, EPA calculated the ADC and LADC as
described in Section 2.4.1.1 and shown in Table 2-57.
Page 159 of 753

-------
Table 2-57. Worker Exposure to Methylene Chloride for During Use of Adhesive and
Caulk Removers"




Data Qualify




Rating of

.Number
Central

Associated Air

of
Tendency
Iligh-Knd
Concentration

Samples
(in /nr')
(ing/nr')
Data
8-hr TWA Exposure




Concentration

1,500
3,000

Average Daily Concentration
(ADC)
unknown
350
680
High
Lifetime Average Daily




Concentration (LADC)

600
1,500

Source: U.S. EPA (20.1.4)
a - No data for ONUs were found; EPA assumes that ONU exposures are less than worker exposures.
Table 2-58 summarizes available short-term exposure data from paint stripping using methylene
chloride, which is assumed to be similar to use of adhesive and caulk removers.
Table 2-58. Short-Term Exposure to Methylene Chloride During Use of Adhesive and
Caulk Removers




Data Quality


Central

Rating of

Number
Tendency

Associated Air

of
(Midpoint)
Iligh-Knd
Concentration

Samples
(nig/nr5)
(mg/nr*)
Data
Professional Contractors
unknown
7,100
14,000
High
Source: U.S. EPA (20.1.4)
Note: The OSHA Short-term exposure limit (STEL) is 433 mg/m3 as a 15-min TWA. Durations of the short-term
samples in the summary data set are not known.
EPA did not identify personal or area data on or parameters for modeling potential ONU
inhalation exposures. Since ONUs do not directly handle formulations containing methylene
chloride, EPA expects ONU inhalation exposures to be lower than worker inhalation exposures.
Information on processes and worker activities are insufficient to determine the proximity of
ONUs to workers and sources of emissions, so relative exposure of ONUs to workers cannot be
quantified.
Table 2-59 presents modeled dermal exposures during adhesive and caulk removal.
Page 160 of 753

-------
Table 2-59. Summary of Dermal Exposure Doses to Methylene Chloride for Adhesive and
Caulk Removers
Occupational
Kxposure
Scenario
I se Sell in
(Industrial vs.
Com in ercial)
Maximum
Weight
Traction.
^ iIitih'1
Dermal K\|
(m/
Central
Tendency
)osurc Dose
.lay)1'
High KihI
Calculated
Traction
Absorbed.
r iiiiN
Adhesive and
Caulk Removers
Commercial
0.9
85
260
0.13
a - EPA's Use and Market Profile for Methylene Chloride (U.S. EPA. 2017g) lists commercial products containing
up to 90% methylene chloride.
b - Conditions where no gloves are used, or for any glove / gauntlet use without permeation data and without
employee training (PF = 1).
Potential impacts of protection factors are presented as what-if scenarios in the dermal exposure summary Table
2-85.
In summary, dermal and inhalation exposures are expected for this scenario. EPA has described
uncertainties for this scenario in Section 4.4.2.
EPA considered the assessment approach, the quality of the data, and uncertainties in assessment
results to determine a level of confidence for the 8-hr TWA data. For the inhalation air
concentration data, the primary strengths include the assessment approach, which is the use of
monitoring data, the highest of the inhalation approach hierarchy. These monitoring data include
>4 data points from 1 source, and the data quality ratings from systematic review for these data
were high. The primary limitations of these data include the age of the data (pre-PEL rule) and
uncertainty of the representativeness of these data toward the true distribution of inhalation
concentrations for the industries and sites covered by this scenario. The analysis of pre- and post-
rule OSHA data (summarized in Table 2-26) did not have enough data to compare pre- to post-
rule mean exposure concentrations for this OES. Additional uncertainties are that the data
available were compiled from a secondary source, which only presented the high, median, and
low values. Based on these strengths and limitations of the inhalation air concentration data, the
overall confidence for these 8-hr TWA data in this scenario is medium to low. The overall
confidence of the dermal dose results is medium (full discussion in Section 2.4.1.3).
2.4.1.2.12 Fabric Finishing
Finkel (2017) submitted workplace monitoring data obtained from a FOIA request of OSHA.
EPA extracted relevant monitoring data by crosswalking the Standard Industrial Classification
(SIC) codes in the dataset with potentially relevant NAICS codes as discussed in the
supplemental document "Risk Evaluation for Methylene Chloride (Dichlorome thane, DCM)
CASRN: 75-09-2, Supplemental Information on Releases and Occupational Exposure
Assessment"(EPA.., 2019b). For the set of 38 data points, 8-hr TWA exposure concentrations
ranged from 0.11 to 331.3 mg/m3. Worker activity information was not available; therefore it
was not possible to specifically attribute the exposures to fabric finishing process, nor to
distinguish workers from ONUs. While additional activities are possible at these sites, such as
use of spot cleaners or general cleaning solvents that contribute to methylene chloride exposures,
EPA assumes that exposures are representative of worker exposures during fabric finishing.
Page 161 of 753

-------
Sample times also varied; EPA assumed that any measurement longer than 15 minutes was done
to assess compliance with the 8-hr TWA PEL, as opposed to the 15-minute STEL, and averaged
all applicable data points over 8 hours. Additional discussion of data treatment is included in
Appendix H. An additional two data points were provided by OSHA for a presser (0.8 mg/m3 -
used as worker exposure) and a finishing department supervisor (1.2 mg/m3 - used as ONU
exposure) (OSHA. 2019). Lists of all inhalation monitoring data found in data sources and
associated systematic review data quality ratings are available in Appendix A of the
supplemental document "Risk Evaluation for Methylene Chloride (Dichlorome thane, DCM)
CASRN: 75-09-2, Supplemental Information on Releases and Occupational Exposure
Assessment"(EPA. 2019b).
Overall, 39 personal monitoring data samples were available for workers and one sample
available for ONUs; EPA calculated the 50th and 95th percentile 8-hr TWA concentrations to
represent a central tendency and high-end estimate of potential occupational inhalation
exposures, respectively, for this scenario. The central tendency 8-hr TWA exposure
concentration for workers is approximately one order of magnitude less than the OSHA PEL
value of 87 mg/m3 (25 ppm) as an 8-hr TWA, while the high-end estimate for workers is
approximately twice the PEL value. Exposure concentrations for ONUs based on the single data
point are an order of magnitude less than the PEL value. Of the 39 worker data points, 25 were
pre-PEL rule, 10 were from the transition period, and 4 were post-PEL rule. The single ONU
data point was post-PEL (see Section 2.4.1.1 for pre-PEL, transition, and post-PEL rule periods).
Using these 8-hr TWA exposure concentrations, EPA calculated the ADC and LADC as
described in Section 2.4.1.1 and shown in Table 2-60.
Table 2-60. Worker and ONU Exposure to Me
thylene Chloride During Fabric Finishing




Data Quality




Rating of

Nil in her
Central

Associated Air


-------
Source: Finket (20.1.7): OSHA (20.1.9).
Table 2-61 summarizes available short-term exposure data available from OSHA inspections
Table 2-61. Summary of Personal Short-Term Exposure Data for Methylene Chloride
During Fabric Finishing					
Occn p;il iiii;il
l''.\|)OMII'C
Scenario
Source
Worker
Ac(i\ i(\
Mel In lone
Chloride Short-
Term
C oncen 1 r;i 1 ion
(iiili/iii-4)
l'l\|)osiirc
Diinilioii
(mill)
l);ilii Qii;ilil>
Killing of
Associated Air
(oiicciilmlion
Diilii
All Other
Leather Good
and Allied
Product
Manufacturing
OSHA (20.1.9)
Sprayer of
Methylene
Chloride
10
194 a
High
a - As there are no health comparisons for 2- or 3-hr samples, this data point is presented but not used to calculate
risk.
Table 2-62 presents modeled dermal exposures during fabric finishing.
Table 2-62. Summary of Dermal Exposure Doses to Methylene Chloride for Fabric
Finishing	
Occupational
Kxposure
Scenario
I se Selling
(Industrial vs.
Commercial)
.Maximum
Weigh!
l-'raction.
^ iln in'1
Dermal K\|
(mg/
Central
Tendency
)osurc Dose
.lay)1'
High End
Calculated
l-'raction
Absorbed.
r iiiiN
Fabric Finishing
Commercial
0.95
90
270
0.13
a - EPA's Use and Market Profile for Methylene Chloride (U.S. EPA. 2017g) lists commercial products containing
up to 95% methylene chloride.
b - Conditions where no gloves are used, or for any glove / gauntlet use without permeation data and without
employee training (PF = 1).
Potential impacts of protection factors are presented as what-if scenarios in the dermal exposure summary Table
2-85.
In summary, dermal and inhalation exposures are expected for this scenario. EPA has described
uncertainties for this scenario in Section 4.4.2.
EPA considered the assessment approach, the quality of the data, and uncertainties in assessment
results to determine a level of confidence for the 8-hr TWA data. For the worker inhalation air
concentration data, the primary strengths include the assessment approach, which is the use of
monitoring data, the highest of the inhalation approach hierarchy. These monitoring data include
39 data points from 2 sources, and the data quality ratings from systematic review for these data
were medium (38 data points) and high (1 data point). The primary limitations of these data
include the age of the data (25 data points pre-PEL rule, 10 data points from the transition
period, and 4 data points post-PEL rule) and uncertainty of the representativeness of these data
toward the true distribution of inhalation concentrations for the industries and sites covered by
Page 163 of 753

-------
this scenario. As discussed earlier in this section, key metadata such as worker activity and
sampling descriptions were not available in the Finkel ( ) dataset to specifically attribute
exposures to fabric finishing or to determine whether sampled activities were representative of
full-shift exposures. A comparison of pre- and post-rule OSHA data (summarized in Table 2-26)
shows that mean exposure concentrations decreased by 93.4% from pre- to post-rule. Based on
these strengths and limitations of the inhalation air concentration data, the overall confidence for
the worker 8-hr TWA data in this scenario is low.
For the ONU inhalation air concentration data, the primary strength is the use of post-PEL
monitoring data, the highest of the inhalation approach hierarchy. The primary limitation is that
only one data point is available. The uncertainty of the representativeness of this data point
toward the true distribution of inhalation concentrations for the industries and sites covered by
this scenario. Based on these strengths and limitations of the ONU inhalation air concentration
data, the overall confidence for the ONU 8-hr TWA data in this scenario is low. The overall
confidence of the dermal dose results is medium (full discussion in Section 2.4.1.3).
2.4.1.2.13 Spot Cleaning
Finkel (2017) submitted workplace monitoring data obtained from a FOIA request of OSHA.
EPA extracted relevant monitoring data by crosswalking the Standard Industrial Classification
(SIC) codes in the dataset with the NAICS codes for Industrial Launderers and Dry cleaning and
Laundry Services (except Coin-Operated). For the set of 18 data points, 8-hr TWA exposure
concentrations ranged from 0.1 to 410.4 mg/m3. Worker activity information was not available;
therefore it was not possible to specifically attribute the exposures to spot cleaning, nor to
distinguish workers from ONUs. While additional activities are possible at these sites, such as
use general cleaning solvents that contribute to methylene chloride exposures, EPA assumes that
exposures are representative of worker exposures during spot cleaning. Sample times also varied;
EPA assumed that any measurement longer than 15 minutes was done to assess compliance with
the 8-hr TWA PEL, as opposed to the 15-minute STEL, and averaged all applicable data points
over 8 hours. Lists of all inhalation monitoring data found in data sources and associated
systematic review data quality ratings are available in Appendix A of the supplemental document
" Risk Evaluation for Methylene Chloride (Dichlorome thane, DCM) CASRN: 75-09-2,
Supplemental Information on Releases and Occupational Exposure Assessment" (EPA, 2019b).
EPA calculated the 50th and 95th percentile 8-hr TWA concentrations to represent a central
tendency and high-end estimate of potential occupational inhalation exposures, respectively, for
this scenario. The central tendency value was two orders of magnitude less than the OSHA PEL
value of 87 mg/m3 (25 ppm), while the high end value was approximately two times the OSHA
PEL. Of the 18 data points, 14 were pre-PEL rule, 1 was from the transition period, and 3 were
post-PEL rule (see Section 2.4.1.1 for pre-PEL, transition, and post-PEL rule periods).
Using these 8-hr TWA exposure concentrations, EPA calculated the ADC and LADC as
described in Section 2.4.1.1 and shown in Table 2-63.
Page 164 of 753

-------
Table 2-63. Worker Exposure to IV
ethylene Chloride for During Spot Cleaning"




Dala Qualify




Rating of

Number
Central

Associated Air

of
Tendency
lligh-lnd
Concentration

Samples
(ing/nr')
(ing/nr*)
Dala
8-hr TWA Exposure
Concentration

0.67
190

Average Daily Concentration
(ADC)
18
0.15
42
Medium
Lifetime Average Daily
Concentration (LADC)

0.26
95

Source: Finket (20.1.7)
a - No data for ONUs were found; EPA assumes that ONU exposures are less than worker exposures.
EPA has not identified personal or area data on short term exposures or potential ONU inhalation
exposures. EPA has developed a model to evaluate potential worker and ONU exposures during
spot cleaning for various solvents; however, the specific methylene chloride use rate during spot
cleaning was not reasonably available. This is a critical data gap and other solvent use rates may
not be applicable. EPA classified retail sales workers (e.g., cashiers), sewers, tailors, and other
textile workers as "occupational non-users" because they perform work at the dry cleaning shop,
but do not directly handle dry cleaning solvents. Since ONUs do not directly handle formulations
containing methylene chloride, EPA expects ONU inhalation exposures to be lower than worker
inhalation exposures. Information on processes and worker activities are insufficient to
determine the proximity of ONUs to workers and sources of emissions, so relative exposure of
ONUs to workers cannot be quantified.
Table 2-64 presents modeled dermal exposures during spot cleaning.
Table 2-64. Summary of Dermal Exposure Doses to Methylene Chloride for Spot Cleaning
Occupational
Kxposurc
Scenario
I se Setting
(Industrial \ s.
Commercial)
.Maximum
Weight
l-'raction.
^ ilei in'1
Dermal K\|
(mg/
Central
Tendency
)osurc Dose
.lay)1'
High I nd
Calculated
l-'raction
Absorbed.
r iiiiN
Spot Cleaning
Commercial
0.9
85
260
0.13
a - EPA's Use and Market Profile for Methylene Chloride (U.S. EPA. 2017a") lists commercial products containing
up to 90% methylene chloride.
b - Conditions where no gloves are used, or for any glove / gauntlet use without permeation data and without
employee training (PF = 1).
Potential impacts of protection factors are presented as what-if scenarios in the dermal exposure summary Table
2-85.
In summary, dermal and inhalation exposures are expected for this scenario. EPA has described
uncertainties for this scenario in Section 4.4.2.
Page 165 of 753

-------
EPA considered the assessment approach, the quality of the data, and uncertainties in assessment
results to determine a level of confidence for the 8-hr TWA data. For the inhalation air
concentration data, the primary strengths include the assessment approach, which is the use of
monitoring data, the highest of the inhalation approach hierarchy. These monitoring data include
18 data points from 1 source, and the data quality ratings from systematic review for these data
were medium. The primary limitations of these data include the age of some data (15 data points
pre-PEL rule or transition period and 3 data points post-PEL rule) and uncertainty of the
representativeness of these data toward the true distribution of inhalation concentrations for the
industries and sites covered by this scenario. As discussed earlier in this section, key metadata
such as worker activity and sampling descriptions were not available in the Finkel (2017) dataset
to specifically attribute exposures to spot cleaning or to determine whether sampled activities
were representative of full-shift exposures. A comparison of pre- and post-rule OSHA data
(summarized in Table 2-26) shows that mean exposure concentrations decreased by 94.5% from
pre- to post-rule. Additionally, the data source did not specify specific worker activities;
therefore, the representativeness of these data specifically for spot cleaning is also uncertain.
Based on these strengths and limitations of the inhalation air concentration data, the overall
confidence for these 8-hr TWA data in this scenario is low. The overall confidence of the dermal
dose results is medium to low (full discussion in Section 2.4.1.3).
2.4.1.2.14 Cellulose Triacetate Film Production
EPA found 8-hr TWA data primarily from six studies performed in the 1970s and 1980s. Worker
activities encompassed various areas of CTA production, including preparation, extrusion, and
coating, but each study compiled data into overall statistics for each worker type instead of
presenting separate data points (Ott et at.. 1983a); (Dell et ai. 1999); (TNO (CTVOi 1999). Lists
of all inhalation monitoring data found in data sources and associated systematic review data
quality ratings are available in Appendix A of the supplemental document" Risk Evaluation for
Methylene Chloride (Dichloromethane, DCM) CASRN: 75-09-2, Supplemental Information on
Releases and Occupational Exposure Assessment" (EPA, 2.019b).
Because the individual data points were not available, EPA presents the average of the median,
and average of maximum values as central tendency and high end, respectively, in Table 2-75.
The central tendency and high end 8-hr TWA exposure concentrations for this scenario are
approximately 12 to 16 times the OSHA PEL value of 87 mg/m3 (25 ppm) as an 8-hr TWA,
respectively. All of the data points were pre-PEL rule (see Section 2.4.1.1 for pre-PEL,
transition, and post-PEL rule periods).
Using these 8-hr TWA exposure concentrations, EPA calculated the ADC and LADC as
described in Section 2.4.1.1 and shown in Table 2-65 for CTA film manufacturing.
Page 166 of 753

-------
Table 2-65. Worker Exposure to Methylene Chloride During Cr
"A Film Manufacturing"




Data Quality




Rating of


Central

Associated Air

.Number of
Tendency
Migh-lnd
Concent ration

Samples
(nig/m')
(nig/nr*)
Data
8-hr TWA Exposure Concentration

1,000
1,400

Average Daily Concentration
(ADC)
>166b
240
320
Medium and
Low
Lifetime Average Daily
Concentration (LADC)

410
560
Sources: Dell et at. (.1.999): TNO (CIVO) (.1.999): Oft et at. (1983a)
a - No data for ONUs were found; EPA assumes that ONU exposures are less than worker exposures,
b - Various studies were compiled to determine central tendency and high-end estimates; however, not all indicated
the number of samples. Therefore, actual number of samples is unknown.
Specific short-term data or personal or area data on or parameters for modeling potential ONU
inhalation exposures were not found. Since ONUs do not directly handle methylene chloride,
ONU inhalation exposures could be lower than worker inhalation exposures. Information on
processes and worker activities are insufficient to determine the proximity of ONUs to workers
and sources of emissions, so relative exposure of ONUs to workers cannot be quantified.
Table 2-66 presents estimated dermal exposures during CTA film manufacturing.
Table 2-66. Summary of Dermal Exposure Doses to Methylene Chloride for CTA Film
Manufacturing	
Occupational
Kxposurc
Scenario
I se Selling
(Industrial vs.
Commercial)
.Maximum
Weight
Traction.
^ iIitih'1
Dermal K\|
(mg/
Central
Tendency
)osurc Dose
.lay)1'
High I nd
Calculated
Traction
Absorbed.
r iiiiN
CTA Film
Manufacturing
Industrial
1
60
180
0.08
a - EPA assumes methylene chloride is received at 100% concentration.
b - Conditions where no gloves are used, or for any glove / gauntlet use without permeation data and without
employee training (PF = 1).
Potential impacts of protection factors are presented as what-if scenarios in the dermal exposure summary Table
2-85.
In summary, dermal and inhalation exposures are expected for this scenario. EPA has described
uncertainties for this scenario in Section 4.4.2.
EPA considered the assessment approach, the quality of the data, and uncertainties in assessment
results to determine a level of confidence for the 8-hr TWA data. For the inhalation air
concentration data, the primary strengths include the assessment approach, which is the use of
monitoring data, the highest of the inhalation approach hierarchy. These monitoring data include
>166 data points from 3 sources, and the data quality ratings from systematic review for these
Page 167 of 753

-------
data were medium and low. The primary limitations of these data include the age of the data (all
data were pre-PEL rule) and uncertainty of the representativeness of these data toward the true
distribution of inhalation concentrations for the industries and sites covered by this scenario. The
analysis of pre- and post-rule OSHA data (summarized in Table 2-26) did not have enough data
to compare pre- to post-rule mean exposure concentrations for this OES. An additional
uncertainty for these sources is that only concentration ranges were provided rather than discrete
data points. Based on these strengths and limitations of the inhalation air concentration data, the
overall confidence for these 8-hr TWA data in this scenario is low. The overall confidence of the
dermal dose results is medium (full discussion in Section 2.4.1.3).
2.4.1.2.15 Flexible Polyurethane Foam Manufacturing
EPA found 8-hr TWA data from various sources, and cover activities such as application of mold
release, foam manufacturing (blowing), blending, and sawing in the foam or plastic industry and
tractor trailer construction. Exposures varied from 0.3 mg/m3 from purge operations, to
2,200.9 mg/m3 during laboratory operations (IARC. ; TNO (CIVO). 1999; WHO. 1996b;
Vulcan Chemicals. 1991; Reh and Lushniak. 19c\\ t f \( 1985; Cone Mills Corp. 19c * i, l, <
Chemicals. 1977). Lists of all inhalation monitoring data found in data sources and associated
systematic review data quality ratings are available in Appendix A of the supplemental document
" Risk Evaluation for Methylene Chloride (Dichlorome thane, DCM) CASRN: 75-09-2,
Supplemental Information on Releases and Occupational Exposure Assessment" (EPA, 2019b).
Overall, 84 8-hr TWA personal monitoring data samples were available; EPA calculated the 50th
and 95th percentile 8-hr TWA concentrations to represent a central tendency and high-end
estimate of potential occupational inhalation exposures, respectively, for this scenario. The
central tendency 8-hr TWA exposure concentration for this scenario is approximately 2.5 times
higher than the OSHA PEL value of 87 mg/m3 (25 ppm) as an 8-hr TWA, while the high-end
estimate is almost 12 times higher. Of the 84 data points, 77 were pre-PEL rule, 4 were from the
transition period, and 3 were post-PEL rule (see Section 2.4.1.12.4.1.1 for pre-PEL, transition,
and post-PEL rule periods). There appear to be many diverse uses of methylene chloride in the
PU foam manufacturing industry, which may contribute to the wide range of exposure
concentrations.
Using these 8-hr TWA exposure concentrations, EPA calculated the ADC and LADC. The
results of these calculations are shown in Table 2-67.
Page 168 of 753

-------
Table 2-67. Worker Exposure to Methylene Chloride During Industrial Polyurethane
Foam Manufacturing3	

\ ii in her
of
Sii in pies
Cent ml
Tendency
(in i*/in "*)
Nigh-Knil
(m/nr()
Diilii Qiiiilitv
killing ol'
Associated Air
Concent nitioii
l):ilii
8-hr TWA Exposure Concentration
84
190
1,000
High to Low
Average Daily Concentration (ADC)
44
230
Lifetime Average Daily
Concentration (LADC)
76
510
Sources: IARC (20.1.6): TNO (CI VP) (.1.999): WHO (1996b): Vulcan Chemicals (.1.991): Rett and Lushniak (.1.990):
Cone Mills Corp (1.981a): Cone Mills Corp (1.981b): J	35):PIin Chemicals (.1.977): OSHA (20.1.9)
a - No data for ONUs were found; EPA assumes that ONU exposures are less than worker exposures.
Table 2-68 summarizes available short-term exposure data available from the 1985 EPA
assessment.
Table 2-68. Summary of Personal Short-Term Exposure Data for Methylene Chloride
During Polyurethane Foam Manufacturing			





Data Quality



Methylene

Kilting of



Chloride Short-

Associated
Occupational


Term
Kxposurc
Air
Kxposurc

Worker
Concentration
Duration
Concentration
Scenario
Source
Activity
(nig/m')
(mill)
Data


Foam
Blowing
5.2
360 a



Foam
Blowing
13
360 a



Foam
Blowing
19
360 a

Polyurethane
Foam
Manufacturing
985)
Foam
Blowing
17
360 a
High
Foam
Blowing
5.2
360 a


Foam
38
360 a



Blowing



Foam
Blowing
11
360 a



Nozzle
55
30 b



Cleaning

a - As there are no health comparisons for 6-hr samples, these data points are presented but not used to calculate risk
b - EPA evaluated one sample, with a 30-minute duration, as a 30-minute exposure.
Note: The OSHA Short-term exposure limit (STEL) is 433 mg/m3 as a 15-min TWA.
Page 169 of 753

-------
EPA has not identified personal or area data on or parameters for modeling potential ONU
inhalation exposures. Since ONUs do not directly handle formulations containing methylene
chloride, EPA expects ONU inhalation exposures to be lower than worker inhalation exposures.
Information on processes and worker activities are insufficient to determine the proximity of
ONUs to workers and sources of emissions, so relative exposure of ONUs to workers cannot be
quantified.
Table 2-69 presents modeled dermal exposures during polyurethane foam blowing.
Table 2-69. Summary of Dermal Exposure Doses to Methylene Chloride for Polyurethane
Foam Manufacturing	
Occupational
Kxposure
Scenario
I se Setting
(Industrial vs.
Commercial)
.Maximum
Weight
l-'raction.
^ ilei in'1
Dermal K\|
(mg/
Central
Tendency
)osurc Dose
.lay)1'
High I nd
Calculated
l-'raction
Absorbed.
r iiiiN
Polyurethane
Foam
Manufacturing
Industrial
1
60
180
0.08
a - EPA assumes workers may be exposed to 100% methylene chloride solvent during equipment cleaning,
b - Conditions where no gloves are used, or for any glove / gauntlet use without permeation data and without
employee training (PF = 1).
Potential impacts of protection factors are presented as what-if scenarios in the dermal exposure summary Table
2-85.
In summary, dermal and inhalation exposures are expected for this scenario. In addition to the
uncertainties identified for this scenario discussed in Section 4.4.2, regulations have limited the
use of methylene chloride in polyurethane foam production and fabrication. OAR's July 16,
2007 Final National Emissions Standards for Hazardous Air Pollutants (NESHAP) for Area
Sources: Polyurethane Foam Production and Fabrication (72 FR 38864) prohibited the use of
methylene chloride-based mold release agents at molded and rebond foam facilities, methylene
chloride-based equipment cleaners at molded foam facilities, and the use of methylene chloride
to clean mix heads and other equipment at slabstock facilities. Slabstock area source facilities are
required to comply with emissions limitations for methylene chloride used as an auxiliary
blowing agent, install controls on storage vessels, and comply with management practices for
equipment leaks. The rule also prohibits methylene chloride-based adhesives for foam
fabrication. The effect of these rules on current exposure levels is unclear.
EPA considered the assessment approach, the quality of the data, and uncertainties in assessment
results to determine a level of confidence for the 8-hr TWA inhalation data. The primary
strengths include the assessment approach, which is the use of monitoring data, the highest of the
inhalation approach hierarchy. These monitoring data include 82 data points from 9 sources, and
the data quality ratings from systematic review for these data were high to low. The primary
limitations of these data include the age of the data (77 data points pre-PEL rule, 4 transition
period, and 3 data points post-PEL rule) and uncertainty of the representativeness of these data
toward the true distribution of inhalation concentrations for the industries and sites covered by
Page 170 of 753

-------
this scenario. The analysis of pre- and post-rule OSHA data (summarized in Table 2-26) did not
have enough data to compare pre- to post-rule mean exposure concentrations for this OES. An
additional uncertainty is that some sources provided only concentration ranges rather than
discrete data points. Based on these strengths and limitations of the non-spray inhalation air
concentration data, the overall confidence for these 8-hr TWA data in this scenario is low. The
overall confidence of the dermal dose results is medium (full discussion in Section 2.4.1.3).
2.4.1.2.16 Laboratory Use
Finkel (2.017) submitted workplace monitoring data obtained from a FOIA request of OSHA.
EPA extracted relevant monitoring data by crosswalking the Standard Industrial Classification
(SIC) codes in the dataset with potentially relevant NAICS codes as discussed in the
supplemental document "Risk Evaluation for Methylene Chloride (Dichlorome thane, DCM)
CASRN: 75-09-2, Supplemental Information on Releases and Occupational Exposure
Assessment"(EPA.., 2019b). For the set of 65 data points, 8-hr TWA exposure concentrations
ranged from 0.11 to 371.4 mg/m3. Worker activity information was not available; therefore it
was not possible to specifically attribute the exposures to laboratory activities, nor to distinguish
workers from ONUs. While additional activities are possible at these sites, such as use cleaning
solvents that contribute to methylene chloride exposures, EPA assumes that exposures are
representative of worker exposures during laboratory use. Sample times also varied; EPA
assumed that any measurement longer than 15 minutes was done to assess compliance with the
8-hr TWA PEL, as opposed to the 15-minute STEL, and averaged all applicable data points over
8 hours. EPA also found 8-hr TWA data from a 1989 NIOSH inspection of an analytical
laboratory at Texaco (Texaco Inc. 1993). and from the U.S. Department of Defense (DoD)
(Defense Occupational and Environmental Health Readiness System - Industrial Hygiene
(DQEHRS-IB). 2018). Worker descriptions include laboratory staff, and activities include
sample preparation and transfer. Note that the NIOSH data were for various sample durations;
EPA included samples that were more than 4 hrs long as full-shift exposures and adjusted the
exposures to 8-hr TWAs, assuming that the exposure concentration for the remainder of the time
was zero, because workers were not expected to perform the activities all day. Lists of all
inhalation monitoring data found in data sources and associated systematic review data quality
ratings are available in Appendix A of the supplemental document" Risk Evaluation for
Methylene Chloride (Dichloromethane, DCM) CASRN: 75-09-2, Supplemental Information on
Releases and Occupational Exposure Assessment"(EP A. 2019b).
Overall, 76 8-hr TWA personal monitoring data samples were available; EPA calculated the 50th
and 95th percentile 8-hr TWA concentrations to represent a central tendency and high-end
estimate of potential occupational inhalation exposures, respectively, for this scenario. The
central tendency 8-hr TWA exposure concentration for this scenario is an order of magnitude
lower than the OSHA PEL value of 87 mg/m3 (25 ppm) as an 8-hr TWA, while the high-end
estimate is slightly above the PEL value. Of the 76 data points, 23 were pre-PEL rule, 15 were
during the transition period and 38 were post-PEL rule (see Section 2.4.1.1 for pre-PEL,
transition, and post-PEL rule periods).
Using these 8-hr TWA exposure concentrations, EPA calculated the ADC and LADC as
described in Section 2.4.1.1 and are summarized in Table 2-70.
Page 171 of 753

-------
Table 2-70. Worker Exposure to Methylene C
lloride During Laboratory Usea




Data Qualify




Rating of

Number
Central

Associated Air

of
Tendency
lligh-lnd
Concentration

Samples
(ing/nr*)
(ing/nr*)
Data
8-hr TWA Exposure
Concentration

6.0
100

Average Daily Concentration
(ADC)
76
1.4
23
High and
Medium
Lifetime Average Daily
Concentration (LADC)

2.4
52

Sources: Defense Occupational and Environmental Health Readiness System - Industrial Hygiene (DOEHRS-IH)
(20.1.8); Texaco Inc (.1.993); Mceaminon (1990); OSHA (20.1.9); Finket (20.1.7)
a - No data for ONUs were found; EPA assumes that ONU exposures are less than worker exposures.
Table 2-71 summarizes short-term exposure data available from the same inspections identified
above for the 8-hr TWA data, as well as OSHA inspection data.
Table 2-71. Worker Personal Short-Term Exposure Data for Methylene Chloride During
Laboratory Use					



Mcllnk-nc

Diilii Qu;ili(>



( hloriric

Killing ol'
Occn p;il iiii;il


Short-Term
l'l\|)OMIIV
Associiiled Air
r.\|)nsurc


C oncenI r;i 1 ion
Diinilioii
( oiicoiiI r;it ion
Scenario
Source
\\ orkcr Acli\ il\
(iii^/nr')
(mill)
Diilii


sample concentrating
2.7
233 d



sample sonification
3.9
218 d



sample sonification
4.5
218 d



washing separatory funnels





in sink near continuous
110
10 a



liquid/liquid extraction





column cleaning
10
200 d


Mecatnmon
sample concentrating
30
210 d
Medium

(1.990)
sample concentrating
4.2
234 d


sample concentrating
6.8
198e

Analytical

transferring 100 mL



Laboratory

methylene chloride into
soil samples
9.8
115 d



collecting waste chemicals





& dumping into waste
1,000
24 b



chemical storage




Defense
Miscellaneous lab
3.1
244 d


Occupational
operations


and
Environmental
Miscellaneous lab
operations
3.1
238 d
High

Health Readiness
Sample extraction and
34.7
180e


System -
analysis (3809, OCD)

Page 172 of 753

-------



Mcllnlcnc

Diilii Qu;ilil>



Chloride

Killing ol
Occn p:il iiii;il


Shorl-Term
l'l\|)OMirc
Associiiled Air
I'lxposuiv


( oiiceiili'iiliou
Dui'iiliou
( cinceiiI r;il ion
Scenario
Source
W orkcr Acli\ il\
(niii/in')
(mill)
Diilii

Industrial
(3)Gas Chromatograpy
0.7
154


Hygiene
(GC) Extraction


(DOEHRS-IH)
134: Extraction of PCB in




120181
water samples (Rm 221 -
Prep & Rm 227 - GC)
22.5
130



134: Extraction of total





volatiles (Toxicity





Characteristic Leaching
64.7
130



Procedure (TCLP)) (Rm





227)





Analysis, chemical
1.7
59c



(Laboratory Operations)



Analysis, chemical
2.4
48c



(Laboratory Operations)



LAB ACTIVITIES
3.3
31b



LAB ACTIVITIES
6.4
30b



LAB ACTIVITIES
16.6
30b



LAB ACTIVITIES
3.4
30b



LAB ACTIVITIES
3.4
30b



LAB ACTIVITIES
3.4
30b



LAB ACTIVITIES
3.4
30b



PRO-OOl-Ol





LABORATORY
5.4
30b



CHEMICAL



ANALYSIS/SAMPLING





514A Using Solvents
1830.0
25 b



EXTRACTION OP
3.6
19a



EXTRACTION OP
24.8
19a



(3)GC Extraction
10.4
15a



(3)GC Extraction
10.4
15a



Sample extraction and
62.5
15a



analysis (3809, OCD)



Miscellaneous lab
operations
6.7
15a



EXTRACTION OP
4.6
15a



EXTRACTION OP
4.6
15a



134: Extraction of PCB in





water samples (Rm 221 -
5.3
15a



Prep & Rm 227 - GC)





134: Extraction of total
5.0
15a



volatiles (TCLP) (Rm 227)



PRO-OOl-Ol





LABORATORY
5.4
15a



CHEMICAL



ANALYSIS/SAMPLING



Page 173 of 753

-------



Mellnlene

Diilii Qu;ilil>



Chloride

Killing of
Occn p:il iiii;il


Shorl-Term
l'l\|)OMirc
Associiiled Air
l-lxposure


( onceii 1 r;i 1 ion
Dui'iilion
( cinceiiI r;il ion
Scenario
Source
\\ orker Acli\ il\
(niii/in')
(mini
Diilii


IND-025-10 HM/HW





HANDLING CLEANUP,
6.1
15a



CONTAINER



SAMPLE/OPEN





PRO-001-01





LABORATORY
10.9
15a



CHEMICAL



ANALYSIS/SAMPLING





PRO-001-01





LABORATORY
13.2
15a



CHEMICAL



ANALYSIS/SAMPLING



Laboratory
OSHA (2019)
Organic Prep Lab Tech
ND
53 f
High
Organic Prep Lab Tech
ND
49f
a - EPA evaluated 15 samples, with durations ranging from 10 to 19 minutes, as 15-minute exposures,
b - EPA evaluated 10 samples, with durations ranging from 24 to 31 minutes, as 30-minute exposures,
c - EPA evaluated two samples, with durations ranging from 48 to 59 minutes, as 1-hr exposures,
d - EPA evaluated six samples, with durations ranging from 218 to 244 minutes, as 4-hr exposures,
e - As there are no health comparisons for 2- or 3-hr samples, these data points are presented but not used to
calculate risk.
f - Limit of detection was not provided for these samples, so they were not used to evaluate risk.
Note: The OSHA Short-term exposure limit (STEL) is 433 mg/m3 as a 15-min TWA.
EPA has not identified personal or area data on or parameters for modeling potential ONU
inhalation exposures. Since ONUs do not directly handle products containing methylene
chloride, ONU inhalation exposures could be lower than worker inhalation exposures.
Information on processes and worker activities are insufficient to determine the proximity of
ONUs to workers and sources of emissions, so relative exposure of ONUs to workers cannot be
quantified.
Table 2-72 presents modeled dermal exposures during laboratory use.
Table 2-72. Summary of Dermal Exposure Doses to Methylene Chloride for Laboratory
Use
Occupational
Kxposure
Scenario
I se Sell in
(Industrial vs.
Com in ercial)
.Maximum
Weight
Traction.
^ iIitih'1
Dermal K\|
(m/
Central
Tendency
)osurc Dose
.lay)1'
High I nd
Calculated
Traction
Absorbed.
r iiiiN
Laboratory Use
Commercial
1
94
280
0.13
a - EPA's Use and Market Profile for Methylene Chloride (U.S. EPA, 2017g) lists commercial products containing
up to 100% methylene chloride.
b - Conditions where no gloves are used, or for any glove / gauntlet use without permeation data and without
employee training (PF = 1).
Page 174 of 753

-------
Potential impacts of protection factors are presented as what-if scenarios in the dermal exposure summary Table
2-85.
In summary, dermal and inhalation exposures are expected for this scenario. EPA has described
uncertainties for this scenario in Section 4.4.2.
EPA considered the assessment approach, the quality of the data, and uncertainties in assessment
results to determine a level of confidence for the 8-hr TWA data. For the inhalation air
concentration data, the primary strengths include the assessment approach, which is the use of
monitoring data, the highest of the inhalation approach hierarchy. These monitoring data include
76 data points from 5 sources, and the data quality ratings from systematic review for these data
were high and medium. The primary limitations of these data include the age of some of the data
(23 were pre-PEL rule, 15 were during the transition period and 38 were post-PEL rule) and
uncertainty of the representativeness of these data toward the true distribution of inhalation
concentrations for the industries and sites covered by this scenario. As discussed earlier in this
section, key metadata such as worker activity and sampling descriptions were not available in the
Finkel (2017) dataset to specifically attribute exposures to laboratory activities or to determine
whether sampled activities were representative of full-shift exposures. A comparison of pre- and
post-rule OSHA data (summarized in Table 2-26) shows that mean exposure concentrations
decreased by 38.9% from pre- to post-rule. Based on these strengths and limitations of the
inhalation air concentration data, the overall confidence for these 8-hr TWA data in this scenario
is low. The overall confidence of the dermal dose results is medium (full discussion in Section
2.4.1.3).
2.4.1.2.17 Plastic Product Manufacturing
Finkel (2017) submitted workplace monitoring data obtained from a FOIA request of OSHA.
EPA extracted relevant monitoring data by crosswalking the Standard Industrial Classification
(SIC) codes in the dataset with potentially relevant NAICS codes as discussed in the
supplemental document" Risk Evaluation for Methylene Chloride (Dichlorome thane, DCM)
CASRN: 75-09-2, Supplemental Information on Releases and Occupational Exposure
Assessment"(EPA. 2019b). For the set of 32 data points, 8-hr TWA exposure concentrations
ranged from 0.1 to 1,637.3 mg/m3. Worker activity information was not available; therefore it
was not possible to specifically attribute the exposures to the plastic manufacturing process, nor
to distinguish workers from ONUs. While additional activities are possible at these sites, such as
use of adhesives or cleaning solvents that contribute to methylene chloride exposures, EPA
assumes that exposures are representative of worker exposures during plastics manufacturing.
Sample times also varied; EPA assumed that any measurement longer than 15 minutes was done
to assess compliance with the 8-hr TWA PEL, as opposed to the 15-minute STEL, and averaged
all applicable data points over 8 hours. HSIA provided an additional 20 data points from 2005
through 2017, for production technicians during plastic product manufacturing. Exposure
concentrations ranged from 3.9 to 134.1 mg/m3 (20 samples) (Halogenated Solvents Industry
Alliance. 2018). Additional data were found for various other sources that ranged from 9 mg/m3
to 2,685.1 mg/m3 (for hop area operator) (Fairfax and Porter. 2006); (WHO. 1996b);
(Halogenated Solvents Industry Alliance. 2018); (General Electric Co. 1989). Lists of all
inhalation monitoring data found in data sources and associated systematic review data quality
ratings are available in Appendix A of the supplemental document" Risk Evaluation for
Page 175 of 753

-------
Methylene Chloride (Dichloromethane, DCM) CASRN: 75-09-2, Supplemental Information on
Releases and Occupational Exposure Assessment" (EP A. 2019b).
Overall for the 8-hr TWA, 62 personal monitoring data samples were available for workers, and
two samples were available for ONUs (although one sample was for an OSHA inspector and
may or may not be reflective of industry ONUs); ONUs are employees who work at the facilities
that process and use methylene chloride, but who do not directly handle the material. ONUs may
also be exposed to methylene chloride but are expected to have lower inhalation exposures and
are not expected to have dermal exposures. ONUs for this condition of use may include
supervisors, managers, engineers, and other personnel in nearby production areas. EPA
calculated the 50th and 95th percentile 8-hr TWA concentrations to represent a central tendency
and high-end estimate of potential occupational inhalation exposures, respectively, for this
scenario. The central tendency 8-hr TWA exposure concentrations for workers and ONUs is
approximately ten times lower the OSHA PEL value of 87 mg/m3 (25 ppm) as an 8-hr TWA,
while the high-end estimate for workers is approximately two times higher. Of the 62 worker
data points, 18 were pre-PEL rule, 3 were transition period, and 41 were post-PEL rule. The
ONU exposure values were post-PEL (see Section 2.4.1.1 for pre-PEL, transition, and post-PEL
rule periods)
Using these 8-hr TWA exposure concentrations, EPA calculated the ADC and LADC as
described in Section 2.4.1.1 and are summarized in Table 2-73.
Table 2-73. Worker and ONU Exposure to Methylene Chloride During Plastic Product
Manufacturing
Kxposure
Number of
Samples
(en (nil
Tendency
(nig/nr*)
lligh-lnd
(nig/nr*)
Data Quality
Rating of
Associated Air
Concentration
Data
Workers
8-hr TWA Exposure Concentration
62
8.5
210
High to Low
Average Daily Concentration
(ADC)
1.9
47
Lifetime Average Daily
Concentration (LADC)
3.4
110
ONUs
8-hr TWA Exposure Concentration
2
9.7
10
High
Average Daily Concentration
(ADC)
2.2
2.3
Lifetime Average Daily
Concentration (LADC)
3.9
5.3
Sources: OSHA (20.1.9): Haloeenated Solvents Industry Alliance (20.1.8): Fairfax and Porter (2006): (IPC!
General Electric Co (.1.989): Finite! (20.1.7)
Page 176 of 753

-------
Table 2-74 summarizes available short-term exposure data for workers and ONUs from the same
OSHA inspections identified above for the 8-hr TWA data, as well as short-term data provided
by HSIA (2018). EPA has not identified area data on or parameters for modeling potential ONU
inhalation exposures.
Page 177 of 753

-------
Table 2-74. Worker Short-Term Exposure Data for Methylene Chloride During Plastic
Product Manufacturing	





Diilii Qu;ili(\



Mcllnlcuc

Killing ol



Chloride

Associiilcd



Sliorl- Icrm
l'l\|)OMirc
Air
Occii|);ilion;il


( oucciili'iiliou
Dui'iiliou
( onccii 1 r;i 1 ion
l'l\|)OMII'C Scenario
Source
\\ orkcr Acli\ il\
(iiiii/m")
(mill)
Diilii
Plastic Product
Manufacturing

Plastics
Manufacturer
ND
15 a

OSHA (2019)
28
15a
High

21
20a



Operator
100
13 a



Operator
74
18a



Operator
94
14a



Operator
66
20a



Operator
66
20a



Operator
60
22 b



Operator
130
10a



Operator
66
20a



Operator
100
13 a



Operator
170
8a



Operator
110
12a



Operator
83
15a



Product
120
lla

Plastics Material and
Haloeenated Solvents
Industry Alliance (2018)
technician


Resin Manufacturing
Product
technician
69
19a
High


Product
83
16a



technician




Product
63
21a



technician




Product

15a



technician
OO




Product
83
16a



technician




Product
100
13 a



technician




Product
110
12a



technician




Product
51
26 b



technician


Plastics Material and
OSHA (20.1.9)
CSHO
ND
92
High
Resin Manufacturing
Extruder Operator
20.4
313d
a - EPA evaluated 21 samples, with durations ranging from 8 to 21 minutes, as 15-minute exposures,
b - EPA evaluated 10 samples, with durations ranging from 22 to 26 minutes, as 30-minute exposures.
Page 178 of 753

-------
c - Limit of detection was not provided for this sample, so it was not used to evaluate risk,
d - As there are no health comparisons for ~5-hr samples, this data point is presented but not used to calculate risk.
Note: The OSHA STEL is 433 mg/m3 as a 15-min TWA.
Table 2-75 presents estimated dermal exposures during plastic product manufacturing.
Table 2-75. Summary of Dermal Exposure Doses to Methylene Chloride for Plastic Product
Manufacturing	
Occupational
Kxposure
Scenario
I se Setting
(Industrial vs.
Commercial)
.Maximum
Weight
l-'raction.
^ ilei in'1
Dermal K\|
(mg/
Central
Tendency
)osurc Dose
.lay)1'
High I nd
Calculated
l-'raction
Absorbed.
r iiiiN
Plastic Product
Manufacturing
Industrial
1
60
180
0.08
a - EPA assumes methylene chloride is received at 100% concentration.
b - Conditions where no gloves are used, or for any glove / gauntlet use without permeation data and without
employee training (PF = 1).
Potential impacts of protection factors are presented as what-if scenarios in the dermal exposure summary Table
2-85.
In summary, dermal and inhalation exposures are expected for this scenario. EPA has described
uncertainties for this scenario in Section 4.4.2.
EPA considered the assessment approach, the quality of the data, and uncertainties in assessment
results to determine a level of confidence for the 8-hr TWA data. For the worker inhalation air
concentration data, the primary strengths include the assessment approach, which is the use of
monitoring data, the highest of the inhalation approach hierarchy. These monitoring data include
62 data points from 6 sources, and the data quality ratings from systematic review for these data
were high to low. The primary limitations of these data include the age of some the data (18 data
points pre-PEL rule, 3 data points transition period, and 41 data points post-PEL rule) and
uncertainty of the representativeness of these data toward the true distribution of inhalation
concentrations for the industries and sites covered by this scenario. As discussed earlier in this
section, key metadata such as worker activity and sampling descriptions were not available in the
Finkel (2017) dataset to specifically attribute exposures to plastics manufacturing or to determine
whether sampled activities were representative of full-shift exposures. A comparison of pre- and
post-rule OSHA data (summarized in Table 2-26) shows that mean exposure concentrations
increased by 617% from pre- to post-rule. Based on these strengths and limitations of the worker
inhalation air concentration data, the overall confidence for these 8-hr TWA data in this scenario
is low.
For the ONU inhalation air concentration data, the primary strengths include the assessment
approach, which is the use of monitoring data, the highest of the inhalation approach hierarchy.
These monitoring data include 2 data points from 1 source, and the data quality ratings from
systematic review for these data points was high. The primary limitations of these data points
include the uncertainty of the representativeness of these data toward the true distribution of
inhalation concentrations for the industries and sites covered by this scenario. Both of the data
points were post-PEL rule. Based on these strengths and limitations of the inhalation air
Page 179 of 753

-------
concentration data, the overall confidence for these 8-hr TWA data in this scenario is low. The
overall confidence of the dermal dose results is medium (full discussion in Section 2.4.1.3).
2.4.1.2.18 Lithographic Printing Plate Cleaning
8-hr TWA data are primarily from Finkel (2017). who submitted workplace monitoring data
obtained from a FOIA request of OSHA. EPA extracted relevant monitoring data by
crosswalking the Standard Industrial Classification (SIC) codes in the dataset with the NAICS
codes as discussed in the supplemental document" Risk Evaluation for Methylene Chloride
(Dichloromethane, DCM) CASRN: 75-09-2, Supplemental Information on Releases and
Occupational Exposure Assessment"( 019b). For the set of 50 data points, 8-hr TWA
exposure concentrations ranged from 0.01 to 167 mg/m3. Worker activity information was not
available; therefore, it was not possible to specifically attribute the exposures to use as a
lithographic printing plate cleaner, nor to distinguish workers from ONUs. While additional
activities are possible at these sites, such as use of inks or coatings that contribute to methylene
chloride exposures, EPA assumes that exposures are representative of worker exposures during
lithographic printing plate cleaning. Sample times also varied; EPA assumed that any
measurement longer than 15 minutes was done to assess compliance with the 8-hr TWA PEL, as
opposed to the 15-minute STEL, and averaged all applicable data points over 8 hours. EPA
found additional 8-hr TWA inhalation monitoring data from the 1985 EPA assessment covering
various printers and activities, which ranged from ND (during printing) to 547.9 mg/m3 (during
screen making for commercial letterpress) (44 data points) (EPA. 1985). Additional data were
also obtained from a 1998 occupational exposure study and a 1980 NIOSH inspection of a
printing facility (IJkai et at.. 1998); (Ahrenholz. 1980). Exposure data were for workers involved
in the printing plate/roll cleaning. The 1998 occupational exposure study only presented the min,
mean, and max values for 61 samples, while the 1980 NIOSH inspection included two full-shift
readings (ND to 17.0 mg/m3; ND was assessed as zero). Minimum and maximum values from
reported ranges were used as discrete data points, while calculated statistics such as mean values
were excluded. Lists of all inhalation monitoring data found in data sources and associated
systematic review data quality ratings are available in Appendix A of the supplemental document
" Risk Evaluation for Methylene Chloride (Dichloromethane, DCM) CASRN: 75-09-2,
Supplemental Information on Releases and Occupational Exposure Assessment" (EPA, 2019b).
Overall, EPA calculated the 50th and 95th percentile 8-hr TWA concentrations to represent a
central tendency and worst-case estimate of potential occupational inhalation exposures,
respectively, for this scenario. The central tendency 8-hr TWA exposure concentrations for this
scenario is one order of magnitude lower than the OSHA PEL value of 87 mg/m3 (25 ppm) as an
8-hr TWA, while the high-end estimate is approximately three times higher. Of the 130 worker
data points, 98 were pre-PEL rule, 11 were from the transition period, and 21 were post-PEL
rule.
Using these 8-hr TWA exposure concentrations, EPA calculated the ADC and LADC. The
results of these calculations are shown in Table 2-76 for workers during plastic product
manufacturing.
Page 180 of 753

-------
Table 2-76. Worker Exposure to Methylene Chloride During Printing Plate Cleaning3

Number
Central

Data Quality Rating

ol"
Tendency
Iligh-Knd
of Associated Air

Samples
(mg/m')
(mg/nr')
Concentration Data
8-hr TWA Exposure Concentration

8.7
160

Average Daily Concentration
(ADC)
>130b
2.0
37
High and Medium
Lifetime Average Daily
Concentration (LADC)

3.5
82

Sources: Ukai et at (.1.998):	>85): Afarenhotz (.1.980): Finket (20.1.
a - No data for ONUs were found; EPA assumes that ONU exposures are less than worker exposures,
b - One study indicated that statistics were based on 61 samples, but only provided the minimum, maximum, and
mean values. Another study provided two exposure values, one of which was ND. ND was assessed as zero
Table 2-77 summarizes the available 4-hr TWA exposure data for workers from the same source
identified above for the 8-hr TWA data. Data were taken in two 4-hr shifts.
Table 2-77. Worker Short-Term Exposure Data for Methylene Chloride During Printing
Plate Cleaning 					



.Methylene

Data Quality



Chloride Short-

Rating ol'
Occupational


Term
Kxposurc
Associated Air
Kxposurc

Worker
Concentration
Duration
Concentration
Scenario
Source
Activity
(mg/iir*)
(mill ):l
Data
Lithographic
Printing Plate
Cleaning
Ukai et
0i
Cleaning of
3.5


printing rolls /
940
240
Medium
El.
(1998)
solvent in
3.6
production
480


a - EPA evaluated these samples as 4-hr exposures.
Note: The OSHA Short-term exposure limit (STEL) is 433 mg/m3 as a 15-min TWA.
EPA has not identified personal or area data on or parameters for modeling potential ONU
inhalation exposures. Since ONUs do not directly handle methylene chloride, EPA expects ONU
inhalation exposures to be lower than worker inhalation exposures. Information on processes and
worker activities are insufficient to determine the proximity of ONUs to workers and sources of
emissions, so relative exposure of ONUs to workers cannot be quantified.
Table 2-78 presents estimated dermal exposures during lithographic printing plate cleaning.
Page 181 of 753

-------
Table 2-78. Summary of Dermal Exposure Doses to Methylene Chloride for Lithographic
Printing Plate Cleaner	
Occupational
Kxposure
Scenario
I se Selling
(Industrial vs.
Commercial)
.Maximum
Weight
Traction.
^ iIitih'1
Dermal K\|
(mg/
Central
Tendency
)osurc Dose
.lay)1'
High KihI
Calculated
Traction
Absorbed.
r iiiiN
Lithographic
Printing Plate
Cleaner
Commercial
0.885
84
250
0.13
a - The 2017 Preliminary Use Document (U.S. EPA. 2017b') lists commercial/industrial products containing up to
88.5% methylene chloride.
b - Conditions where no gloves are used, or for any glove / gauntlet use without permeation data and without
employee training (PF = 1).
Potential impacts of protection factors are presented as what-if scenarios in the dermal exposure summary Table
2-85.
In summary, dermal and inhalation exposures are expected for this scenario. EPA has described
uncertainties for this scenario in Section 4.4.2.
EPA considered the assessment approach, the quality of the data, and uncertainties in assessment
results to determine a level of confidence for the 8-hr TWA data. For the inhalation air
concentration data, the primary strengths include the assessment approach, which is the use of
monitoring data, the highest of the inhalation approach hierarchy. These monitoring data include
>130 data points from 4 sources, and the data quality ratings from systematic review for these
data were high and medium. The primary limitations of these data include the age of the data (98
were pre-PEL rule, 11 were from the transition period, and 21 were post-PEL rule) and
uncertainty of the representativeness of these data toward the true distribution of inhalation
concentrations for the industries and sites covered by this scenario. As discussed earlier in this
section, key metadata such as worker activity and sampling descriptions were not available in the
Finkel (2017) dataset to specifically attribute exposures to lithographic printing plate cleaning or
to determine whether sampled activities were representative of full-shift exposures. A
comparison of pre- and post-rule OSHA data (summarized in Table 2-26) shows that mean
exposure concentrations decreased by 47.7% from pre- to post-rule. Based on these strengths and
limitations of the inhalation air concentration data, the overall confidence for these 8-hr TWA
data in this scenario is low. The overall confidence of the dermal dose results is medium (full
discussion in Section 2.4.1.3).
2.4.1.2.19 Miscellaneous Non-Aerosol Industrial and Commercial Uses
EPA compiled various monitoring data for miscellaneous non-aerosol industrial and commercial
settings, including 8-hr TWA data. 8-hr TWA data are from various OSHA inspection at
wholesalers and retail stores, and include generic worker activities, such as plant workers,
service workers, laborers, etc. Exposure concentrations for various workers ranged from ND to
1,294.8 mg/m3 (rP_\_ h_>H5). Lists of all inhalation monitoring data found in data sources and
associated systematic review data quality ratings are available in Appendix A of the
supplemental document" Risk Evaluation for Methylene Chloride (Dichlorome thane, DCM)
Page 182 of 753

-------
CASRN: 75-09-2, Supplemental Information on Releases and Occupational Exposure
Assessment"(EPA. 2019b).
Overall, 108 personal monitoring data samples were available; EPA calculated the 50th and 95th
percentile 8-hr TWA concentrations to represent a central tendency and high-end estimate of
potential occupational inhalation exposures, respectively, for this scenario. The central tendency
8-hr TWA exposure concentrations for workers is approximately three times higher than the
OSHA PEL value of 87 mg/m3 (25 ppm) as an 8-hr TWA, while the high-end estimate for
workers is more than nine times higher. All 108 data points were pre-PEL rule (see Section
2.4.1.1 for pre-PEL, transition, and post-PEL rule periods).
Using these 8-hr TWA exposure concentrations, EPA calculated the ADC and LADC as
described in Section 2.4.1.1. The results of these calculations are shown in Table 2-79 for
workers during plastic commercial non-aerosol use.
Table 2-79. Worker Exposure to Methylene Chloride During Miscellaneous Industrial and
Commercial Non-Aerosol Usea




Data Qualify




Rating of

Nil m her
Central

Associated Air

of
Tendency
Mih-i:nd
Concentration

Samples
(mg/m-')
(in g/m-*)
Data
8-hr TWA Exposure Concentration

57
930

Average Daily Concentration




(ADC)
108
13
210
High
Lifetime Average Daily




Concentration (LADC)

23
480

Sources: EPA (.1.985).
a - No data for ONUs were found; EPA assumes that ONU exposures are less than worker exposures.
EPA has not identified short-term exposure data or personal or area data on or parameters for
modeling potential ONU inhalation exposures. Since ONUs do not directly handle methylene
chloride, EPA expects ONU inhalation exposures to be lower than worker inhalation exposures.
Information on processes and worker activities are insufficient to determine the proximity of
ONUs to workers and sources of emissions, so relative exposure of ONUs to workers cannot be
quantified.
Table 2-80 presents estimated dermal exposures during industrial and commercial non-aerosol
use.
Page 183 of 753

-------
Table 2-80. Summary of Dermal Exposure Doses to Methylene Chloride for Miscellaneous
Industrial and Commercial Non-Aerosol Use
Occupational
Kxposure
Scenario
I se Sell in
(Industrial vs.
Commercial)
.Maximum
Weight
Traction.
^ iIitih'1
Dermal K\|
(ni/
(cnl r;i 1
Tendency
)osurc Dose
.lay)1'
High KihI
Calculated
Traction
Absorbed.
r iiiiN
Miscellaneous
Industrial Non-
Aerosol Use
Industrial
1
60
180
0.08
Miscellaneous
Commercial
Non-Aerosol Use
Commercial
1
94
280
0.13
a - EPA assumes exposure to methylene chloride at up to 100% concentration.
b - Conditions where no gloves are used, or for any glove / gauntlet use without permeation data and without
employee training (PF = 1).
Potential impacts of protection factors are presented as what-if scenarios in the dermal exposure summary Table
2-85.
In summary, dermal and inhalation exposures are expected for this scenario. EPA has described
uncertainties for this scenario in Section 4.4.2.
EPA considered the assessment approach, the quality of the data, and uncertainties in assessment
results to determine a level of confidence for the 8-hr TWA data. For the inhalation air
concentration data, the primary strengths include the assessment approach, which is the use of
monitoring data, the highest of the inhalation approach hierarchy. These monitoring data include
108 data points from 1 source, and the data quality ratings from systematic review for these data
were high. The primary limitations of these data include the age of the data (all data points were
pre-PEL rule) and uncertainty of the representativeness of these data toward the true distribution
of inhalation concentrations for the industries and sites covered by this scenario. The analysis of
pre- and post-rule OSHA data (summarized in Table 2-26) did not have enough data to compare
pre- to post-rule mean exposure concentrations for this OES. Based on these strengths and
limitations of the inhalation air concentration data, the overall confidence for these 8-hr TWA
data in this scenario is medium to low. The overall confidence of the dermal dose results is
medium (full discussion in Section 2.4.1.3).
2.4.1.2.20 Waste Handling, Disposal, Treatment, and Recycling
8-hr TWA data are primarily from Finkel (2017). who submitted workplace monitoring data
obtained from a FOIA request of OSHA. EPA extracted relevant monitoring data by
crosswalking the Standard Industrial Classification (SIC) codes in the dataset with the NAICS
codes as discussed in the supplemental document" Risk Evaluation for Methylene Chloride
(Dichloromethane, DCM) CASRN: 75-09-2, Supplemental Information on Releases and
Occupational Exposure Assessment" (EPA.., 2019b). For the set of 15 data points, 8-hr TWA
exposure concentrations ranged from 0.11 to 107 mg/m3. Worker activity information was not
available; therefore it was not possible to specifically attribute the exposures to waste handling
activities, nor to distinguish workers from ONUs. While additional activities are possible at these
Page 184 of 753

-------
sites, such as use of cleaning solvents that contribute to methylene chloride exposures, EPA
assumes that exposures are representative of worker exposures during waste handling. Sample
times also varied; EPA assumed that any measurement longer than 15 minutes was done to
assess compliance with the 8-hr TWA PEL, as opposed to the 15-minute STEL, and averaged all
applicable data points over 8 hours. EPA's 1985 assessment included three full-shift data points
for solvent reclaimers at solvent recovery sites, ranging from 10.5 to 19.2 mg/m3 (	>5).
The U.S. Department of Defense (DoD) also provided four data points during waste disposal and
sludge operations ranging from 0.4 to 2.3 mg/m3 (Defense Occupational and Environmental
Health Readiness System - Industrial Hygiene (DOEHRS-IB). 2018). Lists of all inhalation
monitoring data found in data sources and associated systematic review data quality ratings are
available in Appendix A of the supplemental document" Risk Evaluation for Methylene Chloride
(Dichloromethane, DCM) CASRN: 75-09-2, Supplemental Information on Releases and
Occupational Exposure Assessment"(EP A, 2019b).
Overall for the 8-hr TWA samples, 22 personal monitoring data samples were available; EPA
assessed the 50th percentile value of 2.3 mg/m3 as the central tendency, and the 95% percentile
value of 81 mg/m3 as the high-end estimate of potential occupational inhalation exposures for
this life cycle stage. The central tendency exposure concentration for this scenario is an order of
magnitude lower than the OSHA PEL value of 87 mg/m3 (25 ppm) as an 8-hr TWA and high-
end 8-hr TWA exposure concentration is slightly lower than the PEL. Of the 22 data points, 18
were pre-PEL rule, while 4 were post-PEL rule (see Section 2.4.1.1 for pre-PEL, transition, and
post-PEL rule periods).
Using these 8-hr TWA exposure concentrations, EPA calculated the ADC and LADC as
described in Section 2.4.1.1 and are summarized in Table 2-81.
Table 2-81. Worker Exposure to Methylene Chloride During Waste Handling and
Disposal"					




Data Qualify




Rating of

N il in her
Central

Associated Air

of
Tendency
Iligh-Knd
Concentration

Samples
(ing/nr')
(mg/nr')
Data
8-hr TWA Exposure
Concentration

2.3
81

Average Daily Concentration
(ADC)
22
0.54
18
High and
Medium
Lifetime Average Daily
Concentration (LADC)

0.93
41

Source: Defense Occupational and Environmental Health Readiness System - Industrial Hygiene (DOEHRS-IH)
(20.1.8): EPA (.1.985): Finite! (20.1.7)
a - No data for ONUs were found; EPA assumes that ONU exposures are less than worker exposures.
Table 2-82 summarizes the available short-term exposure data for workers from the DoD data.
Page 185 of 753

-------
Table 2-82. Worker Short-Term Exposure Data for Methylene Chloride During Waste
Handling and Disposal					



.Methylene

Data Quality



Chloride

Rating of
Occupational


Short-Term
Kxposurc
Associated Air
Kxposure

Worker
Concentration
Duration
Concentration
Scenario
Source
Activity
(nig/m')
(mill)
Data

Defense

2.9
30 a


Occupational and
Transfer
of
solvent
during
waste
2.9
30a


Environmental
1.8
144 b

Waste
Handling
Health Readiness
5.8
158 b

System -
2.7
159 b
High
Industrial
2.8
163 b


Hygiene
disposal
0.8
173 b


(DOEHRS-HD
3.4
156 b

a - EPA evaluated two 30-minute samples as 30-minute exposures.
b - As there are no health comparisons for 2- or 3-hr samples, these data points are presented but not used to
calculate risk
Note: The OSHA Short-term exposure limit (STEL) is 433 mg/m3 as a 15-min TWA.
EPA has not identified personal or area data on or parameters for modeling potential ONU
inhalation exposures. Since ONUs do not directly handle formulations containing methylene
chloride, EPA expects ONU inhalation exposures to be lower than worker inhalation exposures.
Information on processes and worker activities are insufficient to determine the proximity of
ONUs to workers and sources of emissions, so relative exposure of ONUs to workers cannot be
quantified.
Table 2-83 presents estimated dermal exposures during waste handling, disposal, treatment and
recycling.
Table 2-83. Summary of Dermal Exposure Doses to Methylene Chloride for Waste
Handling, Disposal, Treatment, and Recycling	
Occupational
Kxposurc
Scenario
I se Setting
(Industrial vs.
Commercial)
.Maximum
Weight
l-'raction.
^ ilei in'1
Dermal Kx|
(mg/
Central
Tendency
)osurc Dose
.lay)1'
High I nd
Calculated
l-'raction
Absorbed.
r iiiiN
Waste Handling,
Disposal,
Treatment, and
Recycling
Industrial
1
60
180
0.08
a - EPA assumes potential exposure to methylene chloride at 100% concentration for recovered solvent,
b - Conditions where no gloves are used, or for any glove / gauntlet use without permeation data and without
employee training (PF = 1).
Page 186 of 753

-------
Potential impacts of protection factors are presented as what-if scenarios in the dermal exposure summary Table
2-85.
In summary, dermal and inhalation exposures are expected for this scenario. EPA has described
uncertainties for this scenario in Section 4.4.2.
EPA considered the assessment approach, the quality of the data, and uncertainties in assessment
results to determine a level of confidence for the 8-hr TWA data. For the inhalation air
concentration data, the primary strengths include the assessment approach, which is the use of
monitoring data, the highest of the inhalation approach hierarchy. These monitoring data include
22 data points from 3 sources, and the data quality ratings from systematic review for these data
were high. The primary limitations of these data include the age of some of the data (18 data
points pre-PEL rule and 4 data points post-PEL rule) and uncertainty of the representativeness of
these data toward the true distribution of inhalation concentrations for the industries and sites
covered by this scenario. As discussed earlier in this section, key metadata such as worker
activity and sampling descriptions were not available in the Finkel (2017) dataset to specifically
attribute exposures to waste handling or to determine whether sampled activities were
representative of full-shift exposures. The analysis of pre- and post-rule OSHA data
(summarized in Table 2-26) did not have enough data to compare pre- to post-rule mean
exposure concentrations for this OES. Based on these strengths and limitations of the inhalation
air concentration data, the overall confidence for these 8-hr TWA data in this scenario is low.
The overall confidence of the dermal dose results is medium (full discussion in Section 2.4.1.3).
2.4.1.3 Summary of Occupational Exposure Assessment
The following tables summarize the exposures estimated for the inhalation (Table 2-84) and
dermal (Table 2-85) routes for all occupational exposure scenarios, assuming no exposure
reductions due to potential PPE use.
Table 2-84. Summary of Acute and Chronic Inhalation Exposures to Methylene Chloride
for Central and Higher-End Scenarios by Occupational Exposure Scenario 	
Occnpiilioiiiil
Kxposnrc Scenario
Ciilcjioiy'
Acnlc 1 \posiircs
Chronic. Non-
( iinccr I aixisii ivs
Chronic. Ciinccr
l-AiioMircs
(hciiill
Confidence
Killing of Acnlc
r.xposniv
Conccnlriilions
\l.( '. S- (ii
1 W A (in
('cm nil
Tcndcno
12-hr
li/m')
llih
IikI
AIM'. 24-h
(in 54/11
( on (nil
Tcndcno
r TW A
l')
llih
IikI
I.AIM . 24-
img/i
(cnlriil
Tcndcno
lir TWA
11M
llih
IikI
Manufacturing (8-
hr TWA)
Worker
0.36
4.6
0.08
1.1
0.14
2.4
Medium to High
Manufacturing (12-
hr TWA)
Worker
0.45
12
0.15
4.1
0.27
9.3
Medium to High
Processing as a
Reactant
Worker
1.6
110
0.37
25
0.65
55
Low
Processing -
Incorporation into
Formulation
Worker
100
540
23
120
40
280
Low
Repackaging
Worker
8.8
140
2.0
31
3.50
71
Medium to Low
Page 187 of 753

-------
Occnpiilioiiiil
Kxposiirc Scenario
( iik'jioiy1
Acnlc Iaixisiiivs
Chronic. Non-
( iinccr I aixisii ivs
Chronic. Ciinccr
l'l\i)osiircs
(hciiill
Confidence
Killing of Acnlc
l''.\poMirc
Conccnlriilions
Al.( . X-oi
1 W A (ill
( en I nil
1 OlldcilO
12-hr
K/nr')
llilili
l.ii(l
ADC. 24-h
(inii/n
( on (nil
Tcndono
r TW A
r1)
llilili
IikI
I .AIK . 24-
(in^/i
(cnlriil
Tcndono
lir TWA
n M
llilili
IikI
Batch Open-Top
Vapor Decreasing
Worker
170
740
38
170
67
380
Medium to Low
Batch Open-Top
Vapor Decreasing
ONU
86
460
20
100
34
230
Medium to Low
Conveyorized
Vapor Decreasing
Worker
490
1,400
110
320
190
720
Medium to Low
Conveyorized
Vapor Decreasing
ONU
250
900
58
210
100
460
Medium to Low
Cold Cleaning
Worker
280
1,000
64
230
110
510
Medium to Low
Aerosol
Degreasing/
Lubricants
(Monitoring)
Worker &
ONU
6.0
230
1.4
52
2.4
120
Medium to Low
Aerosol
Degreasing/
Lubricants
(Modeled)
Worker
22
79
5.0
18
8.7
40
Medium to Low
Aerosol
Degreasing/
Lubricants
(Modeled)
ONU
0.40
3.3
0.09
0.74
0.16
1.7
Medium to Low
Adhesives (Spray)
Worker
39
560
8.9
130
16
290
Medium to Low
Adhesives (Non-
Spray)
Worker
10
300
2.4
67
4.2
150
Medium
Adhesives/Sealants
(Unknown
Application)
Worker &
ONU
27
690
6.2
160
11
350
Low
Paints and Coatings
(Spray)
Worker
70
360
16
83
28
190
Medium
Paints and Coatings
(Unknown
Application
Method)
Worker
12
260
2.8
60
4.9
130
Low
Adhesive and
Caulk Removers
Worker
1,500
3,000
350
680
600
1,500
Medium to Low
Fabric Finishing
Worker
7.8
140
1.8
31
3.1
70
Low
Fabric Finishing
ONU
1.2
0.27
0.47
0.61
Low
Spot Cleaning
Worker
0.67
190
0.15
42
0.26
95
Low
CTA
Manufacturing
Worker
1,000
1,400
240
320
410
560
Low
Flexible PU Foam
Manufacturing
Worker
190
1,000
44
230
76
510
Medium
Page 188 of 753

-------
Occnpiilioiiiil
Kxposiirc Scenario
( iik'jioiy1
Acnlo Iaixisiiivs
Chronic. Non-
Ciinccr I aixisii ivs
Chronic. Ciinccr
l'l\i)osiircs
(hciiill
( onlidcncc
Killing ol' Acnlc
l'l\|iosiirc
Conccnlriilions
Al.( . X-oi
1 W A (ill
( en I nil
ToihIciio
12-hr
K/nr')
llilili
Ind
ADC. 24-h
(111^/11
( on (nil
1 oii(k'iic\
r 1W A
r1)
llilili
Ind
I .AIK . 24-
(in^/i
(cnlriil
ToihIoiio
lir TWA
n M
llilili
Ind
Laboratory Use
Worker
6.0
100
1.4
23
2.4
52
Low
Plastic Product
Manufacturing
Worker
8.5
210
1.9
47
3.4
110
Low
Plastic Product
Manufacturing
ONU
9.7
10
2.2
2.3
3.9
5.3
Low
Lithographic
Printing Cleaner
Worker
8.7
160
2.0
37
3.5
82
Low
Miscellaneous
Non-Aerosol
Industrial and
Commercial Use
(Cleaning Solvent)
Worker
57
930
13
210
23
480
Medium to Low
Waste Handling,
Disposal,
Treatment, and
Recycling
Worker
2.3
81
0.54
18
0. 93
41
Low
a - Where no ONU data or estimates are available, EPA assumes that ONU exposures are less than worker
exposures in categories indicated as Worker.
Page 189 of 753

-------
Table 2-85. Summary of Dermal Exposure Doses to Methylene Chloride by Occupational
Exposure Scenario and Potentia
Glove Use
Occnp;iliiii;il Mxposuiv Scenario
Miixiiniiin
Weigh 1
l-'i'iKiidii.
^ lIlTIII
1)
( cm ml
PI- = 1
crniiil I'Ainimii
IVink'iio
PI- > 1
v Dose (mu/(l;i
High
PI- = 1
)
IikI
PI- > 1
Manufacturing, Repackaging,
Processing as a Reactant, Processing -
Incorporation into Formulation,
Mixture, or Reaction Product, Waste
Handling, Disposal, Treatment, and
Recycling
1
60
12 (PF = 5)
6 (PF = 10)
3 (PF = 20)
180
36 (PF = 5)
18 (PF = 10)
9 (PF = 20)
Industrial: Use of Adhesives, Use of
Paints and Coatings, Flexible PU Foam
Manufacturing, Batch Open-Top Vapor
Degreasing, Conveyorized Vapor
Degreasing, Cold Cleaning, CTA Film
Production, Plastic Product
Manufacturing, Miscellaneous Non-
aerosol Industrial Uses
1
60
12 (PF = 5)
6 (PF = 10)
3 (PF = 20)
180
36 (PF = 5)
18 (PF = 10)
9 (PF = 20)
Commercial: Use of Adhesives, Use of
Paints and Coatings, Laboratory Use,
Miscellaneous Non-aerosol Commercial
Uses, Commercial Aerosol Products
1
94
19 (PF = 5)
9 (PF = 10)
280
57 (PF = 5)
28 (PF = 10)
Commercial: Fabric Finishing
0.95
90
18 (PF = 5)
9 (PF = 10)
270
54 (PF = 5)
27 (PF = 10)
Commercial: Adhesive and Caulk
Removers, Spot Cleaning
0.9
85
17 (PF = 5)
9 (PF = 10)
260
51 (PF = 5)
26 (PF = 10)
Commercial: Lithographic Printing
Cleaner
0.885
84
17 (PF = 5)
8 (PF = 10)
250
50 (PF = 5)
25 (PF = 10)
Note on Protection Factors (PFs): All PF values are what-if type values where use of PF above 1 is recommended
only for glove materials that have been tested for permeation against the methylene chloride-containing liquids
associated with the condition of use. For scenarios with only industrial sites, EPA assumes that some workers wear
protective gloves and have activity-specific training on the proper usage of these gloves, which assumes a PF of 20.
For scenarios covering a broader variety of commercial and industrial sites, EPA assumes either the use of gloves
with minimal to no employee training, which assumes a PF of 5, or the use of gloves with basic training, which
assumes a PF of 10.
EPA identified primary strengths and limitations and assigned an overall confidence to the
occupational dermal assessment, as discussed below. EPA considered the assessment approach,
the quality of the data, and uncertainties to determine the level of confidence.
The Dermal Exposure to Volatile Liquids Model used for modeling occupational dermal
exposures accounts for the effect of evaporation on dermal absorption for volatile chemicals and
the potential exposure reduction due to glove use. The model does not account for the transient
exposure and exposure duration effect, which likely overestimates exposures. The model
assumes one exposure event per day, which likely underestimates exposure as workers often
come into repeat contact with the chemical throughout their work day. Surface areas of skin
exposure are based on skin surface area of hands from EPA's Exposure Factors Handbook, but
Page 190 of 753

-------
actual surface areas with liquid contact are unknown and uncertain for all occupational scenarios
OESs. For many OESs, the assumption of contact over the full area of two hands likely
overestimates exposures. Weight fractions are usually reported to CDR and shown in other
literature sources as ranges, and EPA assessed only upper ends of ranges. The glove protection
factors are "what-if' assumptions and are uncertain. EPA does not know the actual frequency,
type, and effectiveness of glove use in specific workplaces of the OESs. Except where specified
above, it is unknown whether most of these uncertainties overestimate or underestimate
exposures. The representativeness of the modeling results toward the true distribution of dermal
doses for the OESs is uncertain. These and other limitations are more fully discussed in Section
4.4.2.4.
Considering these primary strengths and limitations, the overall confidence of the dermal dose
results is medium.
2.4.2 Consumer Exposures
Methylene chloride is found in a variety of consumer products and/or commercial products that
are readily available for public purchase at common retailers. These products are found across a
suite of categories and uses as outlined in the Use and Market Profile for Methylene Chloride
(s H ^ T \ 1^4 ). Based on a combination of information gained from individual products
containing methylene chloride and product use scenarios, consumer exposures due to inhalation
or dermal contact were modeled across a suite of identified conditions of use.
2.4.2.1 Consumer Exposures Approach and Methodology
Following problem formulation, EPA compiled a comprehensive list of current products
available for consumer household use. As noted in Section 1.4.1, while the Problem Formulation
included uses such as metal products not covered elsewhere, apparel and footwear care products,
and laundry and dishwashing products without distinguishing between industrial, commercial,
and consumer uses, after additional review, no applicable consumer products were found for
these uses. EPA has determined that there is no known, intended, or reasonably foreseen
consumer use of these products. There are only industrial and commercial uses of methylene
chloride for these conditions of use, and these conditions of use were therefore not further
assessed as consumer uses. Products were grouped into 15 subcategories ranging from 1-10
identified products in each category, but with most characterized by 4 or less (Table 2-86).
Additionally, these products are primarily aerosol in nature, but are found in liquid form as well
for subcategories Adhesives, Adhesives Removers, and Brush Cleaners.
Table 2-86. Evaluated Consumer Uses for Products Containing Methylene Chloride
Consumer I se Subcategory
l-'orm
Number of Products Identified
Adhesives
Liquid
4
Adhesives Remover
Liquid
1
Auto AC Leak Sealer
Aerosol
1
Auto AC Refrigerant Fill
Aerosol
10
Brake Cleaner
Aerosol
3
Brush Cleaner
Liquid
2
Page 191 of 753

-------
Carbon Remover
Aerosol
1
Carburetor Cleaner
Aerosol
3
Coil Cleaner
Aerosol
1
Cold Pipe Insulation Spray
Aerosol
2
Electronics Cleaner
Aerosol
1
Engine Cleaner/Degreaser
Aerosol
2
Gasket Remover
Aerosol
1
Sealants
Aerosol
1
Weld Spatter/Soldering Protectant
Aerosol
1
2.4,2.2 Exposure Routes
As described in Table 2-86, exposures were evaluated for 15 conditions of use for products
containing methylene chloride. For each of the listed conditions of use, inhalation and dermal
exposures were evaluated, with inhalation being the primary route of exposure.
Inhalation
Consumer and bystander inhalation exposure to methylene chloride is expected to be the most
significant route of exposure through the direct inhalation of sprays, vapors and mists. EPA
assumed mists are absorbed via inhalation, rather than ingestion, due to the deposition of vapors
and mists in the upper respiratory tract. This principal exposure pathway is in line with EPA's
2014 risk assessment of methylene chloride paint stripping use, which assumed that inhalation
was the main exposure pathway based on physical-chemical properties (e.g., high vapor
pressure). All fifteen identified consumer use scenarios were evaluated for exposure via the
inhalation pathway to both consumer users and bystanders. The majority of these uses were
evaluated as sprays or aerosol products, but several products (adhesives, adhesive removers, and
brush cleaners) were evaluated as liquids that have the expectation of inhalation of vapors
emitted from the product due to methylene chloride's high vapor pressure.
Dermal
Dermal exposure to consumer uses of methylene chloride was also evaluated. Dermal exposure
may occur via contact with vapor or mist deposition on the skin or via direct liquid contact
during use. Exposures to skin would be expected to evaporate rapidly (0.06 mol/s) based on
physical chemical properties including vapor pressure, water solubility and log Kow, but some
methylene chloride would also dermally absorb. When evaporation of methylene chloride is
reduced or impeded (e.g., continued contact with a methylene chloride-soaked rag), dermal
absorption would be higher due to the longer duration of exposure. These dermal exposures
would be concurrent with inhalation exposures and the overall contribution of dermal exposure
to total exposure is expected to be smaller than via inhalation. Dermal exposures were evaluated
for all 15 consumer use scenarios across a range of user age groups including adults (>21 years),
youths aged 16-20 years and youths aged 11-15 years due to the possible consumer uses of these
products by younger age groups. Bystander dermal exposure was not evaluated as the incidence
of those exposures are expected to be low and not contribute significantly to overall exposure.
Page 192 of 753

-------
Ingestion
Consumers may be exposed to methylene chloride via transfer from hand to mouth, but this
exposure pathway is expected to be limited due to physical chemical properties including dermal
absorption and volatilization from skin. Due to the limited expected exposure to consumers via
this route, EPA did not further assess this pathway.
From Disposal
EPA does not expect exposure to consumers from disposal of consumer products. It is
anticipated that most products will be disposed of in original containers, particularly those
products that are purchased as aerosol cans.
2,4,2,3 Modeling Approach
EPA estimated consumer exposures for all currently known, intended or reasonably foreseen use
scenarios for products containing methylene chloride. A variety of sources were reviewed during
the Systematic Review process to identify these products and/or articles, including:
	Safety Data Sheets (SDS)
	NIH Household Products Database
	The Chemical and Products (CPDat) Database
	Peer-reviewed and gray literature
	Kirk-Othmer Encyclopedia of Chemical Technology
Consumer exposures were assessed for all methylene chloride containing products identified, as
described in Section 2.4.2.1. As no chemical-specific personal monitoring data was identified
during Systematic Review, a modeling approach was used to estimate the potential consumer
exposures. All consumer use scenarios were assessed using EPA's Consumer Exposure Model
Version 2.1.7 (CEM), as described in Section 2.4.2.3.1, for both inhalation and dermal routes.
To characterize consumer exposures, inhalation modeling for each scenario was conducted by
varying one to three key parameters, while keeping all other input parameters constant. The key
varied parameters included:
1)	duration of use per event (minutes/use);
2)	amount of chemical in the product/article (weight fraction); and/or
3)	mass of product/article used per event (grams/use).
Duration of use and amount of chemical used were varied to correspond to the 10th percentile,
50th percentile and 95th percentile values as reported in U.S. EPA (1987) to encompass a range of
possible exposure conditions. Weight fractions were varied based on reported values of
methylene chloride in Material Safety Data Sheet (MSDS) sheets for evaluated products in
individual consumer use scenarios. At times, the given weight fraction was reported as a single
value whereby weight fraction was not varied in the modeling framework. However, oftentimes
the weight fraction for a single product was reported as a range of possible weight fractions
within that product, or if multiple products were identified for a consumer use scenario, the
available weight fractions making up that scenario resulted in a range. In instances, where the
range in weight fractions was <40% of the product, the maximum and minimum values of the
range were evaluated. In instances where the range of possible weight fractions was >40%, the
minimum, maximum, and midpoint weight fractions were used to better evaluate the wider range
Page 193 of 753

-------
of possible exposure conditions. The variation of modeling inputs for the three parameters
resulted in up to 27 different exposure cases per scenario.
For dermal modeling, the varying parameters were limited to duration of use and weight fraction,
since mass of product is not an input for the dermal models used. Therefore, there were up to 9
different exposure cases per scenario for dermal exposure estimates. The model inputs are
described in Section 2.4.2.3.1 for CEM and shown in Tables 2-87, 2-88, and 2-89.
For all product scenarios, both acute and chronic exposures were expected to occur, but only
acute exposures are evaluated here. Acute exposures were defined as those occurring within a
single day; whereas chronic exposures were defined as exposures comprising 10% or more of a
lifetime (EPA. 201 la). The acute exposure metric selected was a 1-hr TWA.
2.4.2.3.1 CEM Model and Scenarios (e.g., table of scenarios).
Consumer exposures have been assessed using CEM for fifteen consumer use scenarios as
described in Section 2.4.2.1.
CEM Version 2.1.7 (EPA. ) was selected for the consumer exposure modeling as the most
appropriate model to estimate consumer exposures to methylene chloride, primarily due to the
lack of chemical-specific emission data and other required input parameter data that are needed
to run more complex indoor air models CEM predicts indoor air concentrations from consumer
product use by implementing a deterministic, mass-balance calculation utilizing an emission
profile determined by implementing appropriate emission scenarios. The advantages of CEM are
the following:
	CEM has been peer-reviewed.
	CEM includes several distinct models (see (EPA. 2017)) appropriate for evaluating
specific product and article types and use scenarios.
	CEM includes pre-populated scenarios for a variety of products and articles, which have
been pre-parameterized with default use patterns, human exposure factors, environmental
conditions, and product-specific properties.
	CEM has flexibility to alter default parameters, with the exception of user and bystander
activity patterns.
	CEM can accommodate chemical-specific inputs.
	CEM uses the same calculation engine to compute indoor air concentrations from a
source as the higher-tier Multi-Chamber Concentration and Exposure Model (MCCEM),
but does not require emission rates and emission factors derived from chamber studies.
2.4.2.3.1.1 Inhalation
CEM predicts indoor air concentrations from product use by implementing a deterministic, mass-
balance calculation selected by the user depending on the relevant submodel (El through E5; see
(EPA. 2017)). The model uses a two-zone representation of the building of use, with Zone 1
representing the room where the consumer product is used and Zone 2 being the remainder of the
building. The product user is placed within Zone 1 for the hour(s) encompassing the duration of
use, while the bystander population remained in Zone 2 during this time period. A bystander
Page 194 of 753

-------
entering the room of use during the period of product use was not modeled since the inhalable air
concentrations they would be exposed to would be similar to the evaluated user scenario.
Following the time period of product use, product users and bystanders follow prescribed activity
patterns and inhale airborne concentrations of those zones.
The general steps of the calculation engine within CEM include:
1.	Introduction of the chemical (i.e., methylene chloride) into the room of use (Zone 1),
2.	Transfer of the chemical to the rest of the house (Zone 2) due to exchange of air
between the different rooms,
3.	Exchange of the house air with outdoor air and,
4.	Summation of the exposure doses as the modeled occupant moves about the house.
EPA applied the default activity pattern in CEM based on the occupant being present in the home
for most of the day. As the occupants move between zones in the model, the associated zonal air
concentrations at each 30-second time step were compiled to reflect the air concentrations a user
and bystanders would be exposed to throughout the simulation period. Depending on the
modeled room of use, it is possible that a user or bystander may enter into that room following
the product use period according to the prescribed activity pattern. For the El and E3 submodels,
the near-field option that captures the higher concentration in the breathing zone of the product
user during use was selected. TWAs were then computed based on these user and bystander
concentration time series per available human health hazard data. For methylene chloride, 1-hr
and 8-hr TWAs were calculated for use in this risk evaluation (see Section 2.4.2.4 "Consumer
Use Scenario Specific Results").
The emissions models used for evaluating methylene airborne concentrations were either the El,
E2, or E3 emissions model depending on the given consumer use scenario (see Table 2-88). The
El model estimates emission and inhalation exposures from a product applied to an indoor
surface (incremental source model) and is mostly applicable to liquid products that are applied to
a surface and evaporate from that surface (e.g., a cleaner). The E2 model estimates emission and
inhalation exposures from a product applied to an indoor surface (double exponential model) and
is applicable to liquid products that are applied to a surface and dry or cure over time (e.g.,
paints). Finally, the E3 model estimates emission and exposure from a sprayed product. For
specifics on the varied emission models utilized, their assumptions, and underlying algorithms,
EPA refers you to the user's guide for CEM (EPA. 2017).
2.4.2.3.1.2 Dermal
For methylene chloride, dermal exposures to products directly contacting skin were evaluated
using either the fraction absorbed submodel (P_DER2a) or the permeability submodel
(P_DER2b) within CEM. The selection of the appropriate submodel was based on whether the
evaluated condition of use was expected to involve dermal contact with impeded or unimpeded
evaporation.
For situations where dermal contact with impeded evaporation was possible (e.g., wiping with a
chemical soaked rag or immersion of dermal surface into the chemical product), the permeability
submodel was utilized. P_DER2b estimates dermal flux based on a permeability coefficient (Kp)
and is based on the ability of a chemical to penetrate the skin layer once contact occurs. It
assumes a constant supply of chemical directly in contact with the skin throughout the exposure
Page 195 of 753

-------
duration. Note the permeability model does not inherently account for evaporative losses (unless
the available flux or Kp values are based on non-occluded, evaporative conditions), which can be
considerable for volatile chemicals in scenarios where evaporation is not impeded. For
methylene chloride, a measured neat dermal permeability coefficient (Kp = 8.66E-03 cm/hr) is
applied based on Schenk et al. (2018). While the permeability model does not explicitly
represent exposures involving such impeded evaporation, the model assumptions make it the
preferred model for an such a scenario. For complete description of this submodel, see the CEM
User's Guide (	).
In contrast, in situations where dermal contact would be expected to result in unimpeded
evaporation, the fraction absorbed submodel (P_DER2a) was utilized. Within this model, the
potential dose is the amount of the chemical contained in bulk material that is applied to the skin
and the absorbed dose is the amount of the substance that penetrates across the dermal barrier.
The model is essentially the measure of two competing processes, evaporation of the chemical
from the skin surface and penetration deeper into the skin. The fraction absorbed is estimated for
methylene chloride based on Frasch and Bunge ( ) and described in full within the CEM
User's Guide (EPA. 2017). This model assumes the skin surface layer is "filled" once during
product use to an input thickness with subsequent absorption over an estimated absorption time.
Due to the submodel's ability to incorporate evaporative processes, it was considered to be more
representative of dermal exposure under unimpeded situations.
As first outlined in Section 2.4.1.1, it is important to note that while occupational and certain
consumer dermal exposure assessments have a common underlying methodology using dermal
fractional absorption, they use different parametric approaches for dermal exposures due to
different data availability and assessment needs. For example, the occupational approach
accounts for glove use using protection factors, while the consumer approach does not consider
glove use since consumers are not expected to always use gloves constructed with appropriate
materials. The consumer approach factors in duration of use because consumer activities as a
function of product duration of use are much better defined and characterized, while duration of
dermal exposure times for different occupational activities across various workplaces are often
not known. Additionally, the consumer dermal exposure assessments include scenario specific
inputs for fractional surface area of the body exposed in certain consumer activities and offers
different default values for film thickness (ranging from 1.88E-03 to 0.01 cm), and skin surface
area (ranging from 10% of both hands to inside of both hands) for different product users across
different life stages (youth to adult) (Table 2-88 and Section 2.4.2.3.2). While these approaches
both represent fractional absorption methodologies, the different models may result in different
exposure values for similar conditions of use.
2.4.2.3.2 CEM Scenario Inputs
The complete CEM model inputs are provided in Supplemental Information on Consumer
Exposure Assessment. A discussion of the key inputs is provided below. The inputs are
categorized into three types: 1) parameters which are the same among all scenarios (Table 2-87);
2) Scenario-specific parameters which were not varied (Table 2-88); and 3) Scenario-specific
Page 196 of 753

-------
scenarios which were varied to obtain the range of exposure estimates (Table 2-89). A discussion
of key inputs is provided below.
2.4.2.3.2.1 Fixed Scenario Inputs
Parameters used that were the same across all consumer use modeling scenarios parameters are
shown in Table 2-87 and described briefly below. They include populations modeled for both
inhalation and dermal exposure, receptor exposure factors and product properties, activity
patterns, and environmental inputs.
Population
For all methylene chloride scenarios, the consumer user was assumed to be an adult (age 21+)
and two youth age groups (16-20 years and 11-15 years), while a non-user bystander can include
individuals of any age. Results are presented for users and non-user bystanders for inhalation
exposures and users only for dermal exposures. Inhalation exposure results are presented as
concentrations encountered by users and non-user bystanders and are independent of age group.
EPA presents all three evaluated user age groups for dermal exposures as reported doses are age
group specific. More information about how generated exposure estimates are used to evaluate
consumer risk for specific age groups can be found in Section 4.2
Receptor Exposure Factors and Product Properties
Default receptor exposure factors in CEM, as determined from the Exposure Factors Handbook
(EPA. 201 la) were used for body weight and inhalation rate during and after use. Aerosol
fraction was set at the CEM default of 0.06. Exposure duration remained a value of 1 for acute
exposures. For calculation of dermal exposure, the skin permeability coefficient was based on a
neat value of 8.66E-03 (Schenk et at. 2018).
Activity Patterns and Product Use Start Time
The activity pattern selected for the user (i.e., room/building location throughout the exposure
period on an hourly basis) was the default "stay-at-home" resident which places the user
primarily in the home during and after use of the product. The activity patterns were developed
based on Consolidated Human Activity Database (CHAD) (Isaacs. 2014) data of activity
patterns.
The use environment (room of product use) was the default in CEM for pre-populated scenarios,
unless professional judgement was used based on review of specific product information and/or
consumer behavior pattern data in the U.S. EPA (1987) survey of product users for various
consumer product categories. In all cases, the product use was assumed to start at 9:00 AM in the
morning.
Environmental Inputs
All environmental inputs (building volume, air exchange, interzonal air flow) were based on a
residence environment and used CEM default values obtained from Exposure Factors Handbook
(EPA. 201 la). Building volume (492 m3) is used to calculate air concentrations in Zone 2 and
room volume is used to calculate air concentrations in Zone 1 (see below). The volume of the
near-field bubble in Zone 1 was assumed to be 1 m3 in all cases, with the remaining as the far-
field volume. The default interzonal air flows are a function of the overall air exchange rate and
volume of the building, as well as the "openness" of the room itself. Kitchens, living rooms,
Page 197 of 753

-------
garages, schools, and offices are considered to be more open to the rest of the home or building
of use; bedrooms, bathrooms, laundry rooms, and utility rooms are usually accessed through one
door and are considered more closed. Background concentration was set to a CEM default value
of 0 mg/m3.
Table 2-87. Fixed Consumer Use Scenario Modeling Parameters
Parameter
1 nils
Value / Description
MODEL SELECTION / SCENARIO INPUTS
Pathways Selected
n/a
Inhalation and Dermal
Inhalation Model
n/a
Inhalation of Product Used in Environment (Near-
Field / Far-Field) ( P INH2)
Emission Rate
n/a
Let CEM Estimate Emission Rate
Product User (s)
n/a
Adult (>21 years) and Youth (Age 11-20 years)
Activity Pattern
n/a
User Stays at home entire day
Product Use Start Time
n/a
9:00 AM
Background Concentration
mg/m3
0
PRODUCT/ARTICLE PROPERTIES
Frequency of Use (Acute)
events/day
Fixed at 1 event/day (CEM default)
Aerosol Fraction
-
CEM default (0.06)
Fraction Product Ingested
n/a
0
Skin Permeability Coefficient
cm/hr
8.66E-03 (Schenk et al. 2018)
Product Dilution Factor
unitless
Fixed at 1 (i.e., no dilution)
ENVIRONMENT INPUTS
Building Volume (Residence)
m3
492
Air Exchange Rate, Zone 1
(Residence)
hr"1
CEM default (0.45)
Air Exchange Rate, Zone 2
(Residence)
hr"1
CEM default (0.45)
Air Exchange Rate, Near-Field
Boundary
hr"1
CEM default (402)
2.4.2.3.2.2. Non-varying Scenario Specific Inputs
Consumer use non-varying scenario specific inputs for evaluation of inhalation and dermal
exposure are shown in Table 2-88 and described in more detail below.
Product Density
Product density was derived for each consumer use scenario from individual product derived
information found on company websites and/or available SDSs. As multiple products with
Page 198 of 753

-------
varying densities may be found within the same use scenario, the highest reported density was
used in the CEM modeling.
Dermal Exposure Inputs
For the evaluation of dermal exposures from the use of methylene chloride, multiple scenario
specific inputs were used. Surface area to body weight ratio inputs were based on whether the
evaluated COU was run with the CEM Absorption or CEM Permeability submodel. For those
condition of use scenarios run with the CEM Absorption submodel (P_DER2a) a 10% of both
hands SA/BW ratio was selected since product contact with dermal surfaces would likely be
limited. For those scenarios run with the CEM Permeability submodel (P_DER2b) an inside of
one hand or both hands SA/BW ratio was selected based on whether the evaluated COU was
expected to have a situation where product use would involve wiping (e.g., a methylene chloride
soaked rag) or full immersion of both hands respectively (e.g., cleaning a brush). Film thickness
was input based on CEM scenario specific default inputs or set to a default value of 0.01 cm.
Amount of chemical retained on skin is a calculated parameter dependent on film thickness and
methylene chloride density for the given use scenario. Absorption fraction was input based on
neat value given in Schenk et al. (2018)
Room of use
The input room of use is based on information derived from U.S. EPA (1987) for developed use
scenarios, CEM scenario default inputs, or information on chemical use from product labeling or
company websites.
2.4.2.3.2.3. Scenario specific varied inputs
Consumer use non-varying scenario specific inputs for evaluation of inhalation and dermal
exposure are shown in Table 2-89 and described in more detail below.
Duration of Use
The amount of time that a product is used per event was based on the U.S. EPA (1987) survey of
consumer behavior patterns. The most representative product use category in the survey was
selected for each scenario assessed. This input parameter was varied using the 10th, 50th, and 95th
values.
Product Weight Fractions
Product weight fractions were determined from review of product SDSs and any other
information identified during Systematic Review. This input parameter was varied using the 10th,
50th, and 95111 values, unless only single products were identified. Different weight fractions
could potentially make a product more or less efficient in time used or amount used however,
EPA is not able to quantify that change.
Mass of Product Used
The amount of product used per event was based on the U.S. EPA (1987) survey of consumer
behavior patterns. The most representative product use category in the survey was selected for
each scenario assessed. This input parameter was varied using the 10th, 50th, and 95111 values.
Page 199 of 753

-------
Table 2-88. Consumer Use Non-Varying Scenario Specific Inputs for Evaluation of Inha
('oilSlllllcr
Conditions of I so
I 'd nil
(# of Prod.)1
Selected ( I' M
2.l.( Modeling
Scenario2
Product
Density
(ii/cnrV
l-'.m issitui
Model
Applied4
Derm id
l-lxposnrc
Model
Applied*
Dei'iiiid
S A/IJW '
Derm id
l-ilm
Thickness
(cm)
Amouni
Relumed
oil Skin
(/cnrf
Absorption
lr;ic(inns
Room ol
Use
(mJ)9
Adhesives
Liquid
(4)
Glue and
Adhesives
(small scale)
1.375
El
P_DER2a
10% of
hand
surface
area
4.99E-03
0.012
0.017
Utility
Room
(20)
Adhesives Remover
Liquid
(1)
Adhesive/Caulk
Removers, 12
years
1.114
E2
P_DER2b
Inside of
one hand
0.01
0.011
0.089
Utility
Room
(20)
Automotive AC
Leak Sealer
Aerosol
(1)
Generic Product
0.994
E3
P_DER2a
10% of
hand
surface
area
0.01
0.010
0.134
Garage
(90)
Automotive AC
Refrigerant
Aerosol
(10)
Generic Product
1.208
E3
P_DER2a
10% of
hand
surface
area
0.01
0.012
0.134
Garage
(90)
Brake Cleaner
Aerosol
(3)
Degreasers
1.5322
E3
P_DER2b
Inside of
one hand
0.01
0.007
0.033
Garage
(90)
Brush Cleaner
Liquid
(2)
Paint Strippers/
Removers
0.9032
E2
P_DER2b
Inside of
both
hands
1.88E-03
0.011
0.134
Utility
Room
(20)
Carbon Remover
Aerosol
(1)
Degreasers
1.17
E3
P_DER2b
Inside of
one hand
0.01
0.012
0.062
Kitchen
(24)
Carburetor Cleaner
Aerosol
(3)
Degreasers
1.13
E3
P_DER2b
Inside of
one hand
0.01
0.015
0.033
Garage
(90)
Coil Cleaner
Aerosol
(1)
Generic Product
1.34
E3
P_DER2b
Inside of
one hand
0.01
0.013
0.062
Kitchen
(24)
Cold Pipe Insulating
Spray
Aerosol
(2)
Generic Product
1.2
E3
P_DER2a
10% of
hand
surface
area
0.01
0.002
0.017
Kitchen
(24)
Electronics Cleaner
Aerosol
(1)
Degreasers
1.27
E3
P_DER2a
10% of
hand
surface
area
0.01
0.013
0.017
Living
Room
(50)
ation and Dermal Exposure
Page 200 of 753

-------





Derm id

Derm id
Amount




Soloclod CI-.M
Product
l-'.m issitui
l-lxposurc

l-ilm
Kcliiincd

Room ol'
CoilMlllHT
I 'd nil
2.l.( Modeling
l)onsi(\
Model
Model
Derm ;d
Thickness
on Skin
Absorption
Use
Conditions of I so
(# of Prod.)1
Scenario2
(ii/cnrV
Applied4
Applied"
S A/IJW '
(cm)
(ii/enrf
l-'i'iicl iuis
(m3)9
1 !iiginc (leaner
(2)
1 k'grcascrs
i n
E3
iM)i:u:h
Inside nf
one hand
0 01
(><)|2
u 1 U
Garage
(90)
Gasket Remover
Aerosol
(1)
Degreasers
1.038
E3
P_DER2b
Inside of
one hand
0.01
0.010
0.062
Garage
(90)
Sealant
Aerosol
(1)
Generic Product
1.05
E3
P_DER2a
10% of
hand
surface
area
0.01
0.001
0.062
Garage
(90)
Weld Spatter
Aerosol
Generic Product
1.31
E3
P DER2a
10% of
0.01
0.009
0.017
Utility
Protectant
(1)




hand
surface
area



Room
1 Number of products identified for a condition of use scenario is based on product lists within EPA's 2017 Market and use Report.


2 The listed CEM 2.1.6 modeling scenario reflects the default product options within the model, which are prepopulated with certain default parameters. However, due to
EPA choosing to select and vary many key inputs, the specific model scenario matters less than the associated emission and dermal exposure models (e.g., El, E3,
P_DER2a).










3 Selected product densities were primarily sourced from product SDSs and MSDSs unless otherwise noted. Where a range of densities was identified for a given
condition of use, the highest reported product density was used.







4 Selected emissions model used is based on CEM scenario used or best professional judgement.





5 Selected dermal model is based on selection of absorption model for dermal exposure evaluation.




6 Selected dermal surface area to body weight (SA/BW) ratio used is based on CEM scenario used or best professional judgement for Generic Scenario.

7 The amount retained on the skin is an estimated parameter within CEM based on film thickness and chemical density.



8 Absorption fraction is an estimated parameter with CEM with values varying based on exposure time. Values shown here represent values derived from 10th percentile
time used scenarios. Values would differ for 50th and 95th percentile time of use (see Table 2-91).
9 Room of use is either default scenario option within CEM. based on survev results from U.S. EPA (1987). or derived from product use information on product labels or
websites.










Page 201 of 753

-------
Table 2-89. Consumer Use Scenario Specific Values of Duration of Use, Weight Fraction, and Mass of Product Used Derived from
WU.S. EPA (1987)					



Diii'iiliou of I so



Miiss of Product I scd




(mill)





(!i. |n/|)4



Soli-clod I .S. I-'.PA
I .S. I.PA il)S7) Sooiiiirio
Woiiihl Iniction



Consumer

I I'JX"7) Sur\o\

Percentile
(V-'ii mcllnlcnc c
llnrido)'
I .S. I1PA (I'JX"7) Scenario Percenlile
Conditions of I so
l-'orm
Scenario"

50"i.
<)5""
Min
Mid
Msi\
10%
50"-;.

Adhesives
Liquid
Contact Cement,
Super Glues, and
Spray Adhesives
0.33
4.25
60
30
60
90
1.22
[0.03]
10.16
[0.25]
175.65
[4.32]
Adhesives Remover
Liquid
Adhesive Removers
3
60
480
50

75
22.07
[0.67]
263.53
[8]
2108.22
[64]
Automotive AC
Aerosol
Engine
5
15
120
1



88.18

Leak Sealer

Cleaners/Degreasers







[3]

Automotive AC
Aerosol
Engine
5
15
120
1

3
103.95
414.36
1714.59
Refrigerant

Cleaners/Degreasers






[2.91]
[11.6]
[48]
Brake Cleaner
Aerosol
Brake
Quieters/Cleaners
1
15
120
10
35
60
45.31
[1 oz]
181.23
[4]
724.91
[16]
Brush Cleaner
Liquid
Paint
Removers/Strippers
5
60
420
1


71.31
[2.67]
427.32
[16]
3418.58
[128]
Carbon Remover
Aerosol
Solvent-type
Cleaning Fluids or
Degreasers
2
15
120
40

70
19.37
[0.56]
112.44
[3.25]
1107.10
[32]
Carburetor Cleaner
Aerosol
Carburetor Cleaner
1
7
45
20
45
70
41.77
[1.25]
167.07
[5]
644.89
[19.3]
Coil Cleaner
Aerosol
Solvent-type
Cleaning Fluids or
Degreasers
2
15
120
60

100
22.19
[0.56]
128.78
[3.25]
1267.96
[32]
Cold Pipe Insulating
Aerosol
Rust Removers
0.25
5
60
30

60
15.97
77.00
521.61
Spray








[0.45]
[2.17]
[14.70]
Electronics Cleaner
Aerosol
Specialized
Electronic Cleaners
0.17
2
30
5


1.50
[0.04]
18.78
[0.50]
281.65
[7.50]
Engine Cleaner
Aerosol
Engine
Cleaners/Degreasers
5
15
120
20
45
70
97.24
[2.91]
387.60
[11.60]
1603.88
[48]
Gasket Remover
Aerosol
Gasket Remover
2
15
60
60

80
29.77
[0.97]
122.77
[4]
790.05
[25.74]
Page 202 of 753

-------
Consumer
Conditions of I so
Ifiiin
Soli-clod I .S. I PA
(IWiSunoj
Sooiiiirio1
l)ur;ilion of I so
(mill)
I .S. I.PA il'W) Sooiiiirio
Poroonlilo
10%- 50% T 95"
Weight I'molioii
("ii mollnlono chloride)1
Min Mid M;i\
Miiss of Product I sod
(ii. |o/|)4
I .S. I.PA (I9X"7) Sooiiiirio Poreenlile
10%	50%	95%
Sealant
Aerosol
Gasket Remover
15
60
10
30
30.12
[0.97]
124.19
[4]
799.19
[25.74]
Weld Spatter
Protectant
Aerosol
Rust Removers
0.25
60
90
17.43
[0.45]
84.06
[2.17]
569.43
[14.70]
1	U.S. EPA (1987) was used to inform values used for duration of use and mass of product used. Where exact matches for conditions of use were not available,
scenario selection was based on product categories that best met the description and usage patterns of the identified consumer conditions of use.
2	Low-end durations reported by U.S. EPA (1987) that are less than 0.5 minutes (30 seconds) are modeled as being equal to 0.5 minutes due to that being the
minimum timestep available within the model used.
3	The range in weight fractions is reflective of the identified products containing methylene chloride and not reflective of hypothetical functionality-based limits.
Weight Fractions were primarily sourced from product SDSs and MSDSs unless otherwise noted. For information selection of weight faction values, see Section
2.4.2.3.2.3.
4	Mass of product used within U.S. EPA (.1.987) for given scenarios is reported in ounces, but was converted to grams for use within CEM. Conversion to grams
involved using reported density in SDSs and MSDSs for products within a condition of use. Therefore, mass of product used may vary for conditions of use where
the same Westat (1987) scenario was used. See Table 2-90 for selected product densities.	
Page 203 of 753

-------
2.4.2.3.3 Sensitivity Analysis
The CEM developers conducted a detailed sensitivity analysis for CEM version 1.5. A
discussion of that sensitivity analysis is presented in Appendix G and is described in full within
Appendix C of the CEM User Guide (EPA. 2017). In brief, the analysis was conducted on non-
linear, continuous variables and categorical variables that were used in CEM models. A base run
of different models using various product or article categories along with CEM defaults was used
(see Table 1 of Appendix C in U.S. EPA (2017)). Individual variables were modified, one at a
time, and the resulting Chronic Average Daily Dose (CADD) and Acute Dose Rate (ADR) were
then compared to the corresponding results for the base run.
2,4.2.4 Consumer Use Scenario Specific Results
Consumer use scenarios for 15 different conditions of use for both possible inhalation and
dermal exposures were evaluated across a range of user intensities based on differences in
duration of use, weight fraction and mass of product used. While up to 27 different scenarios
were evaluated for inhalation and 18 scenarios for dermal exposure, for the purposes of
presenting the inhalation and dermal results, three combinations are presented to provide results
across a range of use patterns modeled. EPA uses the following descriptors for these three use
patterns: high intensity, moderate intensity, and low intensity use. These descriptors are based on
three key input parameters varied during the modeling (duration of use, weight fraction, and
mass of product used) which are summarized in Section 2.4.2.4.2.3 and Table 2-89 but included
here for ease of reference.
For inhalation results, high intensity use refers to the model iteration that utilized the 95th
percentile duration of use and mass of product used (as presented in U.S. EPA (1987)) and the
maximum weight fraction derived from product specific SDS, when available. Moderate
intensity use refers to the model iteration that utilized the median (50th percentile) duration of use
and mass of product used (as presented U.S. EPA (1987)) and the midpoint weight fraction
derived from product specific SDS, when available. In instances where only two weight fractions
were modeled, the maximum weight fraction was used to represent the moderate intensity user.
Low intensity use refers to the model iteration that utilized the 10th percentile duration of use and
mass of product used (as presented in U.S. EPA (1987)) and the minimum weight fraction
derived from product specific SDS, when available. For dermal results, only the duration of use
and weight fraction inputs were varied across scenarios. Characterization of high intensity,
moderate intensity uses and low intensity users following the same protocol as those described
for the inhalation results, but only encompassing the two varied parameters. For certain
situations, only a single value was identified for weight fraction in the product specific SDS. For
those situations, that parameter is labeled single value and the same value is used in all three use
patterns in the summary tables below.
2.4.2.4.1 Adhesives
Four consumer products used as an adhesive were found to contain methylene chloride in weight
fractions between 30% - 90% (Table 2-90). Inhalation exposures were evaluated for users and
bystanders for 27 different scenarios of duration of use, weight fraction and mass of use. Three
scenarios are presented below as low intensity user, high intensity user and moderate intensity
user scenarios, with 1-hr maximum TWA concentrations ranging from 4.2 - 1,576 mg/m3 for
Page 204 of 753

-------
users and from 0.38 - 200 mg/m3 for bystanders across scenarios. Dermal exposures were
evaluated for nine scenarios using the CEM Fraction Absorbed submodel. Selected scenarios
representing low intensity user, moderate intensity user and high intensity user scenarios ranged
from 4.0E-02 - 2.5 mg/kg/day across all evaluated scenarios and age groups (Table 2-91).
Table 2-90. Consumer User and Bystander Inhalation Exposure to
Methylene Chloride During Use as an Adhesive
Scenario
Description
Dm nil ion
of I so
(mill)
Weight
l-'niclion
(%)
Mjiss of
I so
21 years)
2.5
High Intensity User
Youth (16-20 years)
2.4

Youth (11-15 years)
2.6
Moderate Intensity
User
50%
(4.25)
Midpoint
(60)
Adult (>21 years)
0.60
Youth (16-20 years)
0.56
Youth (11-15 years)
0.62

10%
(0.33)1
Min
(30)
Adult (>21 years)
4.3E-02
Low Intensity User
Youth (16-20 years)
4.0E-02

Youth (11-15 years)
4.4E-02
'Low-end durations reported by U.S. EPA (.1.987) that are less than 0.5 minutes (30 seconds) are modeled as being
equal to 0.5 minutes due to that being the minimum timestep available within the model used.
Page 205 of 753

-------
2.4.2.4.2 Adhesive Remover
A consumer product used as an adhesive remover were found to contain methylene chloride in
weight fractions between 50% - 75% (Table 2-92). Inhalation exposures were evaluated for users
and bystanders for 18 different scenarios of duration of use, weight fraction and mass of use.
Three scenarios are presented below as low intensity user, high intensity user and moderate
intensity user scenarios, with 1-hr maximum TWA concentrations ranging from 1.3-74 mg/m3
for users and from 0.29 - 20 mg/m3 for bystanders across scenarios. Dermal exposures were
evaluated for six scenarios using the CEM Permeability submodel. Selected scenarios
representing low intensity user, moderate intensity user and high intensity user scenarios ranged
from 0.70 - 183 mg/kg/day across all evaluated scenarios and age groups (Table 2-93).
Table 2-92. Consumer User and Bystander Inhalation Exposure to Methylene
Chloride During Use as an Adhesives Remover
Scenario
Description
Diii'iilion
or I se
(mill)
Weight
Inulion
(%)
Miiss of
I se
(Si)
Product
I ser or
liystiiiuler
1 lir Max
TWA
(in "/m*)
S lir Max
TWA
(mg/m()
High Intensity
95%
Max
95%
User
74
68
User
(480)
(75)
(2108.22)
Bystander
62
18
Moderate
50%
Max
50%
User
49
8.1
Intensity User
(60)
(75)
(265.53)
Bystander
6.3
1.9
Low Intensity
10%
Min
10%
User
3.3
0.50
User
(3)
(50)
(22.07)
Bystander
0.29
8.9E-02
Table 2-93. Consumer Dermal Exposure to Methylene Chloride During Use as an
Adhesive Remover


Weight


Scenario
Diimtion of I se
Traction

Acute ADR
Description
(min)
(%)
Receptor
(ing/kg/tlay)
High Intensity
User
95%
(480)
Max
(75)
Adult (>21 years)
179
Youth (16-20 years)
168
Youth (11-15 years)
183
Moderate Intensity
User
50%
(60)
Max
(75)
Adult (>21 years)
22
Youth (16-20 years)
21
Youth (11-15 years)
23
Low Intensity
User
10%
(3)
Min
(50)
Adult (>21 years)
0.75
Youth (16-20 years)
0.70
Youth (11-15 years)
0.76
Page 206 of 753

-------
2.4.2.4.3 Auto AC Leak Sealer
An automotive AC leak sealant containing methylene chloride was identified as available for
consumer use with a weight fraction of <1% (Table 2-94). Inhalation exposures were evaluated
for users and bystanders for three different scenarios of duration of use, weight fraction and mass
of use. One-hour maximum TWA concentrations ranged from 4.0 - 7.0 mg/m3 for users and
from 0.75 - 0.83 mg/m3 for bystanders across scenarios. Dermal exposures were evaluated for
three scenarios using the CEM Fraction Absorbed submodel and ranged from 1.5E-02 - 4.2E-02
mg/kg/day across all evaluated scenarios and age groups (Table 2-95).
Table 2-94. Consumer User and Bystander Inhalation Exposure to Methylene Chloride
During Auto Leak Sealer Use					
Scenario
Description
l)iir;ilion
of I se
(mill)
Wei hl
linclion
(%)
Muss of
I se
(a)
Prodiicl I ser
or livsliinder
1 lir M:i\
TWA
(m/nr()
S lir M:i\
TWA
(m/nr()
High Intensity
User
95%
(120)
Single
Value
(1)
Single
Value
(88.18)
User
4.0
1.1
Bystander
0.75
0.30
Moderate
Intensity User
50%
(15)
Single
Value
(1)
Single
Value
(88.18)
User
6.8
1.1
Bystander
0.83
0.27
Low Intensity
User
10%
(5)
Single
Value
(1)
Single
Value
(88.18)
User
7.0
1.1
Bystander
0.82
0.26
Table 2-95. Consumer Dermal Exposure to Methylene Chloride During Use as an Auto
Leak Sealer
Scenario
Description
Duration of
I se
(mill)
Weight Traction
(%)
Ueceplor
Acute ADU
(mg/kg/dav)
High
Intensity
User
95%
(120)
Single Value
(1)
Adult (>21 years)
4.1E-02
Youth (16-20 years)
3.8E-02
Youth (11-15 years)
4.2E-02
Moderate
Intensity
User
50%
(15)
Single Value
(1)
Adult (>21 years)
3.2E-02
Youth (16-20 years)
3.0E-02
Youth (11-15 years)
3.3E-02
Low
Intensity
User
10%
(5)
Single Value
(1)
Adult (>21 years)
1.7E-02
Youth (16-20 years)
1.5E-02
Youth (11-15 years)
1.7E-02
2.4.2.4.4 Auto AC Refrigerant
Ten consumer products used as an automotive AC refrigerant were found to contain methylene
chloride in weight fractions of <1% - 3% (Table 2-96). Inhalation exposures were evaluated for
Page 207 of 753

-------
users and bystanders for 18 different scenarios of duration of use, weight fraction and mass of
use. Three scenarios are presented below as low intensity user, high intensity user and moderate
intensity user scenarios, with 1-hr maximum TWA concentrations ranging from 8.3 -233 mg/m3
for users and from 0.96 - 44 mg/m3 for bystanders across scenarios. Dermal exposures were
evaluated for six scenarios using the CEM Fraction Absorbed submodel. Selected scenarios
representing low intensity user, moderate intensity user and high intensity user scenarios ranged
from 1.9E-02 - 0.15 mg/kg/day across all evaluated scenarios and age groups (Table 2-97).
Table 2-96. Consumer User and Bystander Inhalation Exposure to Methylene Chloride
During Auto Air Conditioning Refrigerant Use
Sceiiiirio
Description
Duriilion
of I so
(mill)
Weight
Inulion
(%)
Mjiss of
I se
(a)
Product
I ser or
liysliinder
1 hr M;i\
TWA
(in "/in *)
S hr M:i\
TWA
(m/m()
High Intensity
95%
Max
95%
User
233
62
User
(120)
(3)
(1714.59)
Bystander
44
17
Moderate
50%
Max
50%
User
96
16
Intensity User
(15)
(3)
(414.36)
Bystander
12
3.8
Low Intensity
10%
Min
10%
User
8.3
1.3
User
(5)
(1)
(103.95)
Bystander
0.96
0.31
Table 2-97. Consumer Dermal Exposure to Methylene Chloride During Use as an Auto Air
Conditioning Refrigerant
Scenario Description
Duriilion of
I se
(min)
Weight
l-'i'iu-tion
(%)
Receptor
Acute ADR
(ni/k/il:iv)
High Intensity User
95%
(120)
Max
(3)
Adult (>21 years)
0.15
Youth (16-20 years)
0.14
Youth (11-15 years)
0.15
Moderate Intensity
User
50%
(15)
Max
(3)
Adult (>21 years)
0.12
Youth (16-20 years)
0.11
Youth (11-15 years)
0.12
Low Intensity User
10%
(5)
Min
(1)
Adult (>21 years)
2.0E-02
Youth (16-20 years)
1.9E-02
Youth (11-15 years)
2.1E-02
2.4.2.4.5 Brake Cleaner
Three products used as a brake cleaner were found to contain methylene chloride in weight
fractions between 10% - 60% (Table 2-98). Inhalation exposures were evaluated for users and
bystanders for 27 different scenarios of duration of use, weight fraction and mass of use. Three
scenarios are presented below as low intensity user, high intensity user and moderate intensity
Page 208 of 753

-------
user scenarios, with 1-hr maximum TWA concentrations ranging from 36 - 1,974 mg/m3 for
users and from 4.2 - 371 mg/m3 for bystanders across scenarios. Dermal exposures were
evaluated for nine scenarios using the CEM Permeability submodel. Selected scenarios
representing low intensity user, moderate intensity user and high intensity user scenarios ranged
from 6.4E-02 - 50 mg/kg/day across all evaluated scenarios and age groups (Table 2-99).
Table 2-98. Consumer User and Bystander Inhalation Exposure to Methylene
Chloride During Use as a Brake Cleaner
Scenario
Description
Duriilion
of I so
(mill)
Wei hl
Irnclion
(%)
Miiss of
I so
(Si)
Product
I sor or
livsljuuler
1 hr M:i\
TWA
(in "/in"')
S lir Msix
TWA
(m "/nr')
High Intensity
95%
Max
95%
User
1,974
522
User
(120)
(60)
(724.91)
Bystander
371
146
Moderate
50%
Midpoint
50%
User
490
81
Intensity User
(15)
(35)
(181.23)
Bystander
60
19
Low Intensity
10%
Min
10%
User
36
5.8
User
(1)
(10)
(45.31)
Bystander
4.2
1.3
Table 2-99. Consumer Dermal Exposure to Methylene Chloride During Use as a Brake
Cleaner
Scoiiiirio Description
Duration of I so
(min)
Weight l iitclioii
(%)
Receptor
Acute ADR
(m/k/il:iv)
High Intensity User
95%
(120)
Max
(65)
Adult (>21 years)
49
Youth (16-20 years)
46
Youth (11-15 years)
50
Moderate Intensity
User
50%
(15)
Medium
(35)
Adult (>21 years)
3.6
Youth (16-20 years)
3.4
Youth (11-15 years)
3.7
Low Intensity User
10%
(1)
Low
(10)
Adult (>21 years)
6.8E-02
Youth (16-20 years)
6.4E-02
Youth (11-15 years)
7.0E-02
2.4.2.4.6 Brush Cleaner
Two products used as a brush cleaner were found to contain methylene chloride in weight
fractions <1% (Table 2-100). Inhalation exposures were evaluated for users and bystanders for
nine different scenarios of duration of use, weight fraction and mass of use. Three scenarios are
presented below as low intensity user, high intensity user and moderate intensity user scenarios,
with 1-hr maximum TWA concentrations ranging from 0.21 - 1.8 mg/m3 for users and from
1.9E-02 - 0.65 mg/m3 for bystanders across scenarios. Dermal exposures were evaluated for
three scenarios using the CEM Permeability submodel. Selected scenarios representing low
Page 209 of 753

-------
intensity user, moderate intensity user and high intensity user scenarios ranged from 0.04 - 3.5
mg/kg/day across all evaluated scenarios and age groups (Table 2-101).
Table 2-100. Consumer User and Bystander Inhalation Exposure to Methylene
Chloride During Use as a Brush Cleaner
Scenario
Description
Diinilion
or I se
(mill)
Wei hl
Inulion
(%)
Mjiss of
I si-
tU)
1' rod net
I ser or
livsljuuler
1 lir Max
TWA
(in "/in *)
S lir Msix
TWA (in "/in*)
High Intensity
User
95%
(420)
Single
Value
(1)
95%
(3418.58)
User
1.8
1.52
Bystander
0.65
0.32
Moderate
Intensity User
50%
(60)
Single
Value
(1)
50%
(427.32)
User
1.1
0.18
Bystander
0.14
4.2E-02
Low Intensity
User
10%
(5)
Single
Value
(1)
10%
(71.31)
User
0.21
3.2E-02
Bystander
1.9E-02
5.8E-03
Table 2-101. Consumer Dermal Exposure to Methylene Chloride During Use as a Brush
Cleaner
Scenario Description
Dnriilion of
Use
(mill)
Wei jili I
l-ruction
(%)
Rocoplor
Acme ADR
(ni*/k/cl:i>)
High Intensity User
95%
(420)
Single Value
(1)
Adult (>21 years)
3.4
Youth (16-20 years)
3.2
Youth (11-15 years)
3.5
Moderate Intensity
User
50%
(60)
Single Value
(1)
Adult (>21 years)
0.48
Youth (16-20 years)
0.45
Youth (11-15 years)
0.50
Low Intensity User
10%
(5)
Single Value
(1)
Adult (>21 years)
0.04
Youth (16-20 years)
0.04
Youth (11-15 years)
0.04
2.4.2.4.7 Carbon Remover
One product used as a carbon remover (e.g., to clean appliances, pots and pans, etc.) was found
to contain methylene chloride in weight fractions between 40-70% (Table 2-102). Inhalation
exposures were evaluated for users and bystanders for 18 different scenarios of duration of use,
weight fraction and mass of use. Three scenarios are presented below as low intensity user, high
intensity user and moderate intensity user scenarios, with 1-hr maximum TWA concentrations
ranging from 89- 4,751 mg/m3 for users and from 8.2 - 847 mg/m3 for bystanders across
Page 210 of 753

-------
scenarios. Dermal exposures were evaluated for six scenarios using the CEM Permeability
submodel. Selected scenarios representing low intensity user, moderate intensity user and high
intensity user scenarios ranged from 0.39 - 45 mg/kg/day across all evaluated scenarios and age
groups (Table 2-103).
Table 2-102. Consumer User and Bystander Inhalation Exposure to Methylene
Chloride During Use as a Carbon Remover
Scenario
Description
Duriilion
or I so
(mill)
Wei hl
Inution
(%)
Mjiss of
I so
(a)
Product
I sor or
livst:inclor
1 lir Miix
TWA
(m/m()
S lir Msix
TWA
(m/m()
High Intensity
95%
Max
95%
User
4,751
1,276
User
(120)
(70)
(1107.10)
Bystander
847
311
Moderate
50%
Max
50%
User
896
138
Intensity User
(15)
(70)
(112.44)
Bystander
87
26
Low Intensity
10%
Min
10%
User
89
14
User
(2)
(40)
(19.37)
Bystander
8.2
2.4
Table 2-103. Consumer Dermal Exposure to Methylene Chloride During Use as a Carbon
Remover
Scenario
Description
Duration of
Use
(min)
Weight
Inution
(%)
Receptor
Acute ADR
(m/k/il:iv)

95%
(120)
Max
(70)
Adult (>21 years)
44
High Intensity User
Youth (16-20 years)
41

Youth (11-15 years)
45
Moderate Intensity
User
50%
(15)
Max
(70)
Adult (>21 years)
5.5
Youth (16-20 years)
5.1
Youth (11-15 years)
5.6

10%
(2)
Min
(40)
Adult (>21 years)
0.42
Low Intensity User
Youth (16-20 years)
0.39

Youth (11-15 years)
0.43
2.4.2.4.8 Carburetor Cleaner
Three products used as a carburetor cleaner were found to contain methylene chloride in weight
fractions between 20-70% (Table 2-104). Inhalation exposures were evaluated for users and
bystanders for 27 different scenarios of duration of use, weight fraction and mass of use. Three
scenarios are presented below as low intensity user, high intensity user and moderate intensity
user scenarios, with 1-hr maximum TWA concentrations ranging from 66 - 3,021 mg/m3 for
users and from 7.7 - 428 mg/m3 for bystanders across scenarios. Dermal exposures were
evaluated for nine scenarios using the CEM Permeability submodel. Selected scenarios
Page 211 of 753

-------
representing low intensity user, moderate intensity user and high intensity user scenarios ranged
from 9.5E-02 - 16 mg/kg/day across all evaluated scenarios and age groups (Table 2-105).
Table 2-104. Consumer User and Bystander Inhalation Exposure to Methylene
Chloride During Use as a Carburetor Cleaner

Dm ml ion
Wei hl
Muss of
Product
1 lir M:i\
S lir Msix
Scenario
or I so
liitclioii
I se
I ser or
TWA
TWA
Description
(mill)
(%)
(a)
livstiiniler
(m/m()
(m/m()
High Intensity
95%
Max
95%
User
3,021
525
User
(45)
(70)
(644.89)
Bystander
428
148
Moderate
50%
Midpoint
50%
User
595
97
Intensity User
(7)
(45)
(167.07)
Bystander
70
22
Low Intensity
10%
Min
10%
User
66
11
User
(1)
(20)
(41.77)
Bystander
7.7
2.5
Table 2-105. Consumer Dermal Exposure to Methylene Chloride During Use as a
Carburetor Cleaner
Scenario
Duriilion of I se
Weight l i itclioii

Acute ADR
Description
(min)
(%)
Receptor
(m/k/ihiY)

95%
(45)
Max
(70)
Adult (>21 years)
16
High Intensity User
Youth (16-20 years)
15

Youth (11-15 years)
16
Moderate Intensity
User
50%
(7)
Midpoint
(45)
Adult (>21 years)
1.6
Youth (16-20 years)
1.5
Youth (11-15 years)
1.6

10%
(1)
Min
(20)
Adult (>21 years)
0.10
Low Intensity User
Youth (16-20 years)
9.5E-02

Youth (11-15 years)
0.10
2.4.2.4.9 Coil Cleaner
One product used as a coil cleaner (e.g., air conditioner condensing coils) was found to contain
methylene chloride in weight fractions between 60-100% (Table 2-106). Inhalation exposures
were evaluated for users and bystanders for 18 different scenarios of duration of use, weight
fraction and mass of use. Three scenarios are presented below as low intensity user, high
intensity user and moderate intensity user scenarios, with 1-hr maximum TWA concentrations
ranging from 152 - 7,773 mg/m3 for users and from 14 - 1,387 mg/m3 for bystanders across
scenarios. Dermal exposures were evaluated for six scenarios using the CEM Permeability
submodel. Selected scenarios representing low intensity user, moderate intensity user and high
intensity user scenarios ranged from 0.67 - 74 mg/kg/day across all evaluated scenarios and age
groups (Table 2-107).
Page 212 of 753

-------
Table 2-106. Consumer User and Bystander Inhalation Exposure to Methylene
Chloride During use as a Coil Cleaner
Scenario
Description
Dui'iition
or I so
(mill)
Weight
Inulion
(%)
Mjiss of
I so
(a)
Product
I ser or
livstiindor
1 lir M:i\
TWA
(m/m()
S lir Msix
TWA
(m/m()
High Intensity
95%
Max
95%
User
7,773
2,088
User
(120)
(100)
(1267.96)
Bystander
1,387
509
Moderate
50%
Max
50%
User
1,465
225
Intensity User
(15)
(100)
(128.78)
Bystander
142
42
Low Intensity
10%
Min
10%
User
152
23
User
(2)
(60)
(22.19)
Bystander
14
4.2
Table 2-107. Consumer Dermal Exposure to Methylene Chloride During Use as a Coil
Cleaner
Scenario
Description
Duration of
Use
(min)
Weight
Inulion
(%)
Receptor
Acute ADR
(m/k/chiv)

95%
(120)
Max
(100)
Adult (>21 years)
72
High Intensity User
Youth (16-20 years)
67

Youth (11-15 years)
74
Moderate Intensity
User
50%
(15)
Max
(100)
Adult (>21 years)
9.0
Youth (16-20 years)
8.4
Youth (11-15 years)
9.2

10%
(2)
Min
(60)
Adult (>21 years)
0.72
Low Intensity User
Youth (16-20 years)
0.67

Youth (11-15 years)
0.74
2.4.2.4.10 Cold Pipe Insulation Spray
Two products used as a cold pipe insulation spray were found to contain methylene chloride in
weight fractions between 30-60% (Table 2-108). Inhalation exposures were evaluated for users
and bystanders for 18 different scenarios of duration of use, weight fraction and mass of use.
Three scenarios are presented below as low intensity user, high intensity user and moderate
intensity user scenarios, with 1-hr maximum TWA concentrations ranging from 54 -
2,965 mg/m3 for users and from 5.0 - 390 mg/m3 for bystanders across scenarios. Dermal
exposures were evaluated for six scenarios using the CEM Fraction Absorbed submodel.
Selected scenarios representing low intensity user, moderate intensity user and high intensity
user scenarios ranged from 7.0E-02 - 3.04 mg/kg/day across all evaluated scenarios and age
groups (Table 2-109).
Page 213 of 753

-------
Table 2-108. Consumer User and Bystander Inhalation Exposure to Methylene
Chloride During Cold Pipe Insulation Spray Use
Scenario
Description
Dm nit ion
or I so
(mill)
Weight
liitctioii
(%)
Miiss of
I so
(Si)
Product
I ser or
liystiiiulor
1 hr M:i\
TWA
(m/m()
8 hr Mjix
TWA
(in /m4)
High Intensity
95%
Max
95%
User
2,965
491
User
(60)
(60)
(521.61)
Bystander
390
120
Moderate
50%
Max
50%
User
530
81
Intensity User
(5)
(60)
(77.00)
Bystander
49
15
Low Intensity
10%
Min
10%
User
54
8.2
User
(0.25)1
(30)
(15.97)
Bystander
5.0
1.5
'Low-end durations reported by U.S. EPA (1987) that are less than 0.5 minutes (30 seconds) are
modeled as being equal to 0.5 minutes due to that being the minimum timestep available within the
model used.
Table 2-109. Consumer Dermal Exposure to Methylene Chloride During Use as a Cold
Pipe Insulation Spray
Scenario
Description
Dumtion ol'
Use
(min)
Weight
I'mction
(%)
Receptor
Acute ADR
(ni/k/il;iv)
High Intensity User
95%
(60)
Max
(60)
Adult (>21 years)
2.97
Youth (16-20 years)
2.78
Youth (11-15 years)
3.04
Moderate Intensity
User
50%
(5)
Max
(60)
Adult (>21 years)
1.20
Youth (16-20 years)
1.12
Youth (11-15 years)
1.22
Low Intensity User
10%
(0.25)1
Min
(30)
Adult (>21 years)
7.5E-02
Youth (16-20 years)
7.0E-02
Youth (11-15 years)
7.7E-02
'Low-end durations reported by U.S. EPA (.1.987) that are less than 0.5 minutes (30 seconds) are modeled as being
equal to 0.5 minutes due to that being the minimum timestep available within the model used.
2.4.2.4.11 Electronics Cleaner
One product used as an electronics cleaner was found to contain methylene chloride with a
weight fraction of 5% (Table 2-110). Inhalation exposures were evaluated for users and
bystanders for 9 different scenarios of duration of use, weight fraction and mass of use. Three
scenarios are presented below as low intensity user, high intensity user and moderate intensity
user scenarios, with 1-hr maximum TWA concentrations ranging from 0.72 - 130 mg/m3 for
users and from 0.11 - 27 mg/m3 for bystanders across scenarios. Dermal exposures were
Page 214 of 753

-------
evaluated for three scenarios using the CEM Fraction Absorbed submodel. Selected scenarios
representing low intensity user, moderate intensity user and high intensity user scenarios ranged
from 1.2E-02 - 0.26 mg/kg/day across all evaluated scenarios and age groups (Table 2-111).
Table 2-110. Consumer User and Bystander Inhalation Exposure to Methylene
Chloride During Use as an Electronics Cleaner
Scenario
Description
Duriilion
of I so
(mill)
Wei hl
Inution
(%)
Miiss of
I so
(Si)
Product
I sor or
livsl:iiuler
1 lir M:i\
TWA
(m/m()
S lir Mjix
TWA
(m/m()
High Intensity
User
95%
(30)
Single
Value
(5)
95%
(281.65)
User
130
22
Bystander
27
6.3
Moderate
Intensity User
50%
(2)
Single
Value
(5)
50%
(18.78)
User
9.2
1.5
Bystander
1.3
0.34
Low Intensity
User
10%
(0.17)1
Single
Value
(5)
10%
(1.50)
User
0.72
0.12
Bystander
0.11
2.7E-02
'Low-end durations reported by U.S. EPA (1987) that are less than 0.5 minutes (30 seconds) are
modeled as being equal to 0.5 minutes due to that being the minimum timestep available within the
model used.
Table 2-111. Consumer Dermal Exposure to Methylene Chloride During Use as an
Electronics Cleaner

Duriilion of I sc
Weight l-riii'lion

Acute ADR
Sccnnrio Description
(mill)
(%)
Receptor
(ni/k/d;iv)

95%
(30)
Single Value
(5)
Adult (>21 years)
0.25
High Intensity User
Youth (16-20 years)
0.23

Youth (11-15 years)
0.26
Moderate Intensity
User
50%
(2)
Single Value
(5)
Adult (>21 years)
4.9E-02
Youth (16-20 years)
4.6E-02
Youth (11-15 years)
5.0E-02

10%
(0.17)1
Single Value
(5)
Adult (>21 years)
1.3E-02
Low Intensity User
Youth (16-20 years)
1.2E-02

Youth (11-15 years)
1.4E-02
'Low-end durations reported by U.S. EPA (.1.987) that are less than 0.5 minutes (30 seconds) are modeled as being
equal to 0.5 minutes due to that being the minimum timestep available within the model used.
2.4.2.4.12 Engine Cleaner
Two products used as an engine cleaner were found to contain methylene chloride in weight
fractions between 20-70% (Table 2-112). Inhalation exposures were evaluated for users and
Page 215 of 753

-------
bystanders for 27 different scenarios of duration of use, weight fraction and mass of use. Three
scenarios are presented below as low intensity user, high intensity user and moderate intensity
user scenarios, with 1-hr maximum TWA concentrations ranging from 154 - 5,096 mg/m3 for
users and from 18 - 958 mg/m3 for bystanders across scenarios. Dermal exposures were
evaluated for nine scenarios using the CEM Permeability submodel. Selected scenarios
representing low intensity user, moderate intensity user and high intensity user scenarios ranged
from 0.52 - 23 mg/kg/day across all evaluated scenarios and age groups (Table 2-113).
Table 2-112. Consumer User and Bystander Inhalation Exposure to Methylene
Chloride During Use as an Engine Cleaner
Scenario
Description
Duriilion
of I se
(mill)
Wei hl
liitclion
(%)
M:iss of
I si-
tU)
Product
I ser or
liystiinder
1 hr M;i\
TWA
(in "/in *)
S lir Mjix
TWA
(111 /lll')
High Intensity
95%
Max
95%
User
5,096
1,347
User
(120)
(70)
(1603.88)
Bystander
958
377
Moderate
50%
Midpoint
50%
User
1,347
221
Intensity User
(15)
(45)
(387.60)
Bystander
164
53
Low Intensity
10%
Min
10%
User
154
25
User
(5)
(20)
(97.24)
Bystander
18
5.8
Table 2-113. Consumer Dermal Exposure to Methylene Chloride During Use as an Engine
Cleaner
Scenario Description
Diir;ilion of I so
(min)
Weight Trjiction
(%)
Receptor
Acute ADR
(ni/k/d;iv)
High Intensity User
95%
(120)
Max
(70)
Adult (>21 years)
22
Youth (16-20 years)
21
Youth (11-15 years)
23
Moderate Intensity
User
50%
(15)
Midpoint
(45)
Adult (>21 years)
5.6
Youth (16-20 years)
5.2
Youth (11-15 years)
5.7
Low Intensity User
10%
(5)
Min
(20)
Adult (>21 years)
0.56
Youth (16-20 years)
0.52
Youth (11-15 years)
0.57
2.4.2.4.13 Gasket Remover
One product used as a gasket remover was found to contain methylene chloride in weight
fractions between 60-80% (Table 2-114). Inhalation exposures were evaluated for users and
bystanders for 18 different scenarios of duration of use, weight fraction and mass of use. Three
scenarios are presented below as low intensity user, high intensity user and moderate intensity
user scenarios, with 1-hr maximum TWA concentrations ranging from 142 - 3,769 mg/m3 for
Page 216 of 753

-------
users and from 16 - 590 mg/m3 for bystanders across scenarios. Dermal exposures were
evaluated for six scenarios using the CEM Permeability submodel. Selected scenarios
representing low intensity user, moderate intensity user and high intensity user scenarios ranged
from 0.52 - 23 mg/kg/day across all evaluated scenarios and age groups (Table 2-115).
Table 2-114. Consumer User and Bystander Inhalation Exposure to Methylene
Chloride During Use as a Gasket Remover
Scenario
Description
Dm nit ion
of I sc
(mill)
Weight
Inulion
(%)
Mjiss of
I se
(a)
Product
I scr or
livstiiiulcr
1 lir M:i\
TWA
(m/m()
S lir Msix
TWA
(ni/ni()
High Intensity
95%
Max
95%
User
3,769
682
User
(60)
(80)
(790.05)
Bystander
590
212
Moderate
50%
Max
50%
User
758
125
Intensity User
(15)
(80)
(122.77)
Bystander
92
30
Low Intensity
10%
Min
10%
User
142
23
User
(2)
(60)
(29.77)
Bystander
16
5.3
Table 2-115. Consumer Dermal Exposure to Methylene Chloride During Use as a Gasket
Remover
Sceiiiirio Description
Duriition of
Use
(min)
Weight l iiictioii
(%)
Receptor
Acute ADR
(m/k/il:iv)

95%
(60)
Max
(80)
Adult (>21 years)
22
High Intensity User
Youth (16-20 years)
21

Youth (11-15 years)
23
Moderate Intensity
User
50%
(15)
Max
(80)
Adult (>21 years)
5.6
Youth (16-20 years)
5.2
Youth (11-15 years)
5.7

10%
(2)
Min
(60)
Adult (>21 years)
0.56
Low Intensity User
Youth (16-20 years)
0.52

Youth (11-15 years)
0.57
2.4.2.4.14 Sealants
One product used as a sealant was found to contain methylene chloride in weight fractions
between 10-30% (Table 2-116). Inhalation exposures were evaluated for users and bystanders for
18 different scenarios of duration of use, weight fraction and mass of use. Three scenarios are
presented below as low intensity user, high intensity user and moderate intensity user scenarios,
with 1-hr maximum TWA concentrations ranging from 24 - 1,430 mg/m3 for users and from 2.8
- 224 mg/m3 for bystanders across scenarios. Dermal exposures were evaluated for six scenarios
Page 217 of 753

-------
using the CEM Fraction Absorbed submodel. Selected scenarios representing low intensity user,
moderate intensity user and high intensity user scenarios ranged from 7.6E-02 - 1.3 mg/kg/day
across all evaluated scenarios and age groups (Table 2-117).
Table 2-116. Consumer User and Bystander Inhalation Exposure to Methylene
Chloride During Use as a Sealant
Sceiiiirio
Description
Duriilion
of I se
(mill)
Weight
liitclion
(%)
Miiss of
I se
(a)
Product
I ser or
livsljuuler
1 hr M;i\
TWA
(in "/m*)
S hr Mjix
TWA
(mg/m()
High Intensity
95%
Max
95%
User
1,430
259
User
(60)
(30)
(799.19)
Bystander
224
80
Moderate
50%
Max
50%
User
288
47
Intensity User
(15)
(30)
(124.19)
Bystander
35
11
Low Intensity
10%
Min
10%
User
24
3.9
User
(2)
(10)
(30.12)
Bystander
2.8
0.89
Table 2-117. Consumer Dermal Exposure to Methylene Chloride During Use as a Sealant

Diinilion of
Weight



Use
Inution

Acute ADR
Sceiiiirio Description
(min)
(%)
Receptor
(mg/kg/iliiv)

95%
(60)
Max
(30)
Adult (>21 years)
1.3
High Intensity User
Youth (16-20 years)
1.2

Youth (11-15 years)
1.3
Moderate Intensity
User
50%
(15)
Max
(30)
Adult (>21 years)
1.0
Youth (16-20 years)
0.96
Youth (11-15 years)
1.0

10%
(2)
Min
(10)
Adult (>21 years)
8.1E-02
Low Intensity User
Youth (16-20 years)
7.6E-02

Youth (11-15 years)
8.3E-02
2.4.2.4.15 Weld Spatter Protectant
One product used as a weld spatter protectant was found to contain methylene chloride in weight
fractions >90% (Table 2-118). Inhalation exposures were evaluated for users and bystanders for
nine different scenarios of duration of use, weight fraction and mass of use. Three scenarios are
presented below as low intensity user, high intensity user and moderate intensity user scenarios,
with 1-hr maximum TWA concentrations ranging from 181 -5, 111 mg/m3 for users and from 16
- 648 mg/m3 for bystanders across scenarios. Dermal exposures were evaluated for six scenarios
using the CEM Fraction Absorbed submodel. Selected scenarios representing low intensity user,
Page 218 of 753

-------
moderate intensity user and high intensity user scenarios ranged from 0.23 - 5.0 mg/kg/day
across all evaluated scenarios and age groups (Table 2-119).
Table 2-118. Consumer User and Bystander Inhalation Exposure to
Scenario
Description
Diiriilion
or I se
(mill)
Weight
liiution
(%)
Msiss of
I se
(a)
l> rod ucl
I ser or
livsliiiuler
1 lir M:i\
TWA
(m/m()
S lir Msix
TWA
(m/m()
High
Intensity
User
95%
(60)
Single
Value
(90)
95%
(569.43)
User
5111
836
Bystander
648
198
Moderate
Intensity
User
50%
(5)
Single
Value
(90)
50%
(84.06)
User
897
136
Bystander
81
24
Low
Intensity
User
10%
(0.25)1
Single
Value
(90)
10%
(17.43)
User
181
28
Bystander
16
4.9
'Low-end durations reported by U.S. EPA (1987) that are less than 0.5 minutes (30 seconds) are
modeled as being equal to 0.5 minutes due to that being the minimum timestep available within the
model used.
Table 2-119. Consumer Dermal Exposure to Methylene Chloride During Use as a Weld
Spatter Protectant
Scenario Description
Diii'iition of
Use
(mill)
Weight
linction
(%)
Receptor
Acute ADR
(m/k/iliiv)
High Intensity User
95%
(60)
Single Value
(90)
Adult (>21 years)
4.9
Youth (16-20 years)
4.6
Youth (11-15 years)
5.0
Moderate Intensity
User
50%
(5)
Single Value
(90)
Adult (>21 years)
2.0
Youth (16-20 years)
1.8
Youth (11-15 years)
2.0
Low Intensity User
10%
(0.25)1
Single Value
(90)
Adult (>21 years)
0.25
Youth (16-20 years)
0.23
Youth (11-15 years)
0.25
'Low-end durations reported by U.S. EPA (.1.987) that are less than 0.5 minutes (30 seconds) are modeled as being
equal to 0.5 minutes due to that being the minimum timestep available within the model used.
2,4,2,5 Monitoring Data
2.4.2.5.1 Indoor Residential Air
Page 219 of 753

-------
Concentrations of methylene chloride in the indoor air of residential homes in the U.S. and
Canada from 9 studies identified during Systematic Review are summarized in Table 2-120.
Overall, more than 700 samples were collected between 1986 and 2010 in five U.S. states (CO,
IL, MA, MI, and MN) and Canada (exact location not reported). Concentrations ranged from
non-detect (limits varied) to 1,190 |ig/m3. The highest concentrations were from the Van Winkle
et. al. (2001) study, which notes that the high methylene chloride concentrations are likely
associated with analytical artifacts. Excluding this study, maximum concentrations of 147 and
176 |ig/m3 were observed in garages of residences in Boston, MA (Dodson et al... 2008) and in
inner city homes in New York, NY (Sax et al.. 2004). respectively. Maximum concentrations
were much lower in other studies, generally less than 15 |ig/m3. Excluding the Van Winkle et. al.
(2.001) study, measures of central tendency (reported average or median) across all datasets were
generally less than 10 |ig/m3, except for the Canadian study at 27 |ig/m3.
Data extracted for residential indoor air samples from studies conducted outside of North
America, as well as studies conducted in schools and commercial establishments in the U.S. and
other countries, is provided in Systematic Review Supplemental File: Data Extraction Tables for
Consumer and Environmental Exposure Studies.
Table 2-120. Concentrations of Methylene Chloride in the Indoor Air of Residential Homes
in the U.S. and Canada from Studies Identified During Systematic Review	








l);il;i


Deled.





I.Mll.
Sluclj Info
Silo Ik'scriplion
Limit
Min.
Mciin
Modinii
Msi\.
\ iiriiincc
Score
(CMn el al., 2014);
Detroit, MI area;
0.71
ND
0.54
0.71
7.85
0.91
High
U.S., 2009-2010
Homes (n=126)





(SD)
(n=126; DFq = 0.06)
with asthmatic
children, sampled
in living rooms and
bedroom







(Dodson et at, 2008):
Boston, MA;
0.39-
ND
9.8
0.3
147
36
High
U.S., 2004-2005
Garage of
1.25



(95th)
(SD)

(n=16; DFq = 0.25)
residences







(Dodson et at, 2008):
Boston, MA;
0.39-
ND
2.6
0.4
15
4.6
High
U.S., 2004-2005
(n=10; DFq = 0.2)
Apartment hallway
of residences
1.25



(95th)
(SD)

(Dodson et al., 2008):
Boston, MA;
0.39-
ND
9.5
0.4
0.66
28
High
U.S., 2004-2005
Basement of
1.25



(95th)
(SD)

(n=52; DFq = 0.42)
residences







(Dodson et al, 2008):
Boston, MA;
0.39-
ND
0.28
0.21
10
8.7
High
U.S., 2004-2005
Interior room of
1.25



(95th)
(SD)

(n=83; DFq = 0.4)
residences







(Adgate et al, 2004):
Minneapolis, MN
	b
ND
--
0.3
1.2
--
Medium
U.S., 2000
in spring; Child's

(0.2


(90th)


(n=113; DFq = 0.202)
primary residence

10th)





(Adgate et al, 2004):
Minneapolis, MN
	b
ND
--
0.4
1.3
--
Medium
U.S., 2000
in winter; Child's

(0.2


(90th)


(n=113; DFq = 0.232)
primary residence.

10th)





Page 220 of 753

-------








Diilii


Deled.





I.Mll.
Siuclj lulu
Silo Description
1 Jm il
Min.
Mean
Mediiin
Msi\.
\ iiriiinee
Score
f ./
1 ais \imclcs. (' \ mi
u::
u:
1 4
1 1
4 ^
i:
11 iuIi
U.S., 2000
fall; Homes in





(SD)

(n=32; DFq = 1)
inner-city







(Saxetal., 2004):
Los Angeles, CA in
0.27
0.27
2.4
1.9
8.7
2
High
U.S., 2000
winter; Homes in





(SD)

(n=40; DFq = 0.95)
inner-city







(Saxetal, 2004):
New York, NY in
1.63
1.63
10
1.4
176
32.9
High
U.S., 1999
summer; Homes in





(SD)

(n=30; DFq = 0.28)
inner-city







(Saxetal., 2004):
New York, NY in
0.22
0.2
5.5
2.2
69
12.3
High
U.S., 1999
winter; Homes in





(SD)

(n=36; DFq = 0.97)
inner-city







(Van Winkle and Scheff, Southeast Chicago,
	
0.76c
140c
60.5c
1190
235
High
2001):
IL; Urban homes





(SD)
U.S., 1994-1995
(n=48; DFq = 1)
(n=10) sampled
over a 10-month
period, from the
kitchen in the
breathing zone.







(Lindstrom et al, 199.
5J: Denver, CO;
0.14
0.14
2.64
1.57

2.63
Medium
U.S., 1994 (n=9; DFq
= 0.78) Homes, pre-
occupancy (n=8)





(SD)

(Wallace et al, 1991
U.S., Los Angeles, CA in


5.6

14
1.4
Medium
1991 (n= 8; DFq = 1)
summer; Kitchens
and living-area





(SE)

(Chan et al, 1990):
Homes (n=12),
--
ND
9.1
--
--
--
Medium
Canada, 1986
main floor







(n=12; DFq = 0.92)








(Chan et al, 1990):
Homes (n=6), main

4
26.9



Medium
Canada, 1987
floor







(n=6; DFq = 1)








Abbreviations: If a value was not reported, it is shown in this table as ". ND = not detected at the reported detection limit. GM
= geometric mean. GSD = geometric standard deviation. DFq = detection frequency. NR = Not reported. U.S.
Parameters: All statistics are shown as reported in the study. Some reported statistics may be less than the detection limit; the
method of handling non-detects varied by study. All minimum values determined to be less than the detection limit are shown in
this table as "ND". If a maximum value was not provided, the highest percentile available is shown (as indicated in parentheses);
if a minimum value was not provided, the lowest percentile available is shown (as indicated in parentheses),
a Samples from this study (Dodson et at. 2008) were collected as part of the BEAMS study.
b No quantitative detection limit was provided in Adgate et al. (2004). however Chung et al (.1.999) was cited as the
basis for the precision, accuracy, and suitability of the sampling methodology used. A detection limit of 0.9 ng/m3
was identified within Chung et al. (.1.999) and can be reasonably applied to Adgate et al. (2004) due to the similarities
in their sampling and analytical methodologies.
0 Elevated methylene chloride concentrations likely associated with analytical artifact (Van Winkle and Scheff.
2001).
2.4.2.5.2 Personal Breathing Zone Data
Concentrations of methylene chloride in the personal breathing zones of residents in the U.S.
from two studies identified during Systematic Review are summarized in Table 2-121. Overall,
Page 221 of 753

-------
more than 500 personal monitoring samples from 48-hr monitoring periods were collected
between 1999 and 2000 in one U.S. state (MN). Reported concentrations ranged from non-detect
(limits varied) to 13.6 |ig/m3; and central tendency values (reported mean or median) ranged
from 0.3 to 6.7 |ig/m3. The maximum concentration of 13.6 |ig/m3 is a 90th percentile value
based on an overall average of 70 non-smoking adults during spring, summer, and fall sampling
and spending 89% of their time indoors (home, work, school), 6.4% outdoors, and 4.5% in
transit (Sexton et at.. 2.007). The second study (Adgate et at.. 2.004) observed personal exposure
to methylene chloride for 80 children while spending 66% of their time at home, 25.2% of their
time at school, 1.5% of their time playing outdoors, and 3.8% of their time in transit during the
spring and winter. There was a 10-fold difference between the maximum values reported in the
two studies.
Data extracted for residential personal breathing zone samples from studies conducted outside of
North America, as well as studies conducted in schools and commercial establishments in the
U.S. and other countries, is provided in the Supplemental Information on Consumer Exposure
Assessment (EPA... 2019a).
Table 2-121. Concentrations of Methylene Chloride in the Personal Breathing Zones of
Residents in the U.S.
Sludj lulu
Silo Description
Deled.
I.imil
Min.
Mean
Mediiin
M;i\.
\ iiriiinee
Diilii
I.Mll.
Score
U.S.! 1999
(n=333; DFq =
1)
\lmneapolis-St. Paul, MN;
Non-smoking adults (n=70);
three neighborhoods: (inner-
city/economically
disadvantaged, blue-
collar/near manufacturing
plants, and affluent); indoors,
outdoors, and in transit.

0.4
(10)
6.7
1.4
13.6
(90th)

High
(A dgate et al.,
2004);
U.S., 2000
(n=113; DFq =
0.17)
Minneapolis, MN in spring;
Child's primary residence,
school, outside, and in transit
a
ND
(0.2
10th)

0.3
1.3
(90th)

Medium
(A dgate et al.,
Minneapolis, MN in winter;
Child's primary residence,
school, outside, and in transit.
a
ND
(0.2
10th)

0.4
1.3
(90th)

Medium
2004):
U.S., 2000
(n=113; DFq =
0.194)
Abbreviations: If a value was not reported, it is shown in this table as ". ND = not detected at the reported detection limit.
Parameters: All statistics are shown as reported in the study. Some reported statistics may be less than the detection limit; the
method of handling non-detects varied by study. All minimum values determined to be less than the detection limit are shown in
this table as "ND". If a maximum value was not provided, the highest percentile available is shown (as indicated in parentheses);
if a minimum value was not provided, the lowest percentile available is shown (as indicated in parentheses).
aNo quantitative detection limit was provided in Adgate et al. (2004). however Chung et al (.1.999) was cited as the
basis for the precision, accuracy, and suitability of the sampling methodology used. A detection limit of 0.9 |ig/m3
was identified within Chung et al. (1.999) and can be reasonably applied to Adgate et al. (2004) due to the
similarities in their sampling and analytical methodologies.
Page 222 of 753

-------
2.4.2.6 Modeling Confidence in Consumer Exposure Results
Overall, there is medium to high or high confidence in the consumer inhalation exposure
modeling approach and results (Table 2-122). This is based on the strength of the model
employed, as well as the quality and relevance of the default, user-selected and varied modeling
inputs. CEM 2.1.7 is a peer reviewed, publicly available model that was designed to estimate
inhalation and dermal exposures from household products and articles. CEM uses central-
tendency default values for sensitive inputs such as building and room volumes, interzonal
ventilation rate, and air exchange rates. These parameters were not varied due to EPA having
greater confidence in the central tendency inputs for such factors that are outside of a user's
control (unlike, e.g., mass of product used or use duration). These central tendency defaults are
sourced from EPA's Exposure Factors Handbook (	). The confidence in the user-
selected varied inputs (i.e., mass used, use duration, and weight fraction) are medium to high,
depending on the condition of use. The sources of these data are U.S. EPA (198?) (high-quality)
and company-generated SDSs. What reduces confidence for particular conditions of use is the
relevance or similarity of the U.S. EPA (1987) survey product category for the modeled
condition of use. For instance, the evaluated brake cleaner scenario had surveyed information
directly about this condition of use within U.S. EPA (1987). resulting in a high confidence in
model default values. In contrast, the coil cleaner scenario did not have an exact match within
U.S. EPA (1987). resulting in use of a surrogate scenario selected by professional judgement that
most closely approximates the use amount and duration associated with this condition of use.
Additionally, in some cases, professional judgment or surveyed information from U.S. EPA
(1987) was used in selection of room of use, which sets the volume for modeling zone 1.
Dermal exposure modeling results overall were rated as low to medium (Table 2-123). The
processes and inputs described for the inhalation scenarios above are also valid for the dermal
exposure scenarios. While the model used for dermal exposure estimates was the same as used
for the inhalation exposure estimates, there is overall low to medium (vs. high for inhalation)
confidence in the model used due to the used dermal submodels. As described in Section
2.4.2.3.1.2, the evaluation of dermal exposures used a faction absorbed or permeability submodel
depending on condition of use. Both of these models have inherent assumptions included in their
calculations which may over or underestimate calculated dermal exposures. For instance, the
fraction absorbed submodel assumes that the entire mass of the chemical found in the film
thickness enters the skin. This may overestimate exposure as some surface evaporation would be
expected. Conversely, the model may underestimate exposures since it assumes the given thin
film is only applied once and does not account for situations where multiple application events
may be possible, particularly during high duration conditions of use. The permeability submodel
also may overestimate exposures since it assumes a constant supply of chemical over the length
of the exposure duration. While indicative of impeded exposure conditions, such a scenario is
unlikely as impeded use conditions would be likely to be intermittent and not constant in nature.
These and other assumptions and uncertainties are further discussed in Section 4.3.3.
Page 223 of 753

-------
Table 2-122. Confidence in Individual Consumer Conditions of Use Inhalation Exposure
Evaluations
CoilSllllKT
Condition of
I so
Form
( onl'idcncc
in Model
I sod1
( onI'idcMice
in Model
IKTiiull
\ ;iliics:
( on Hi
Miiss
I sod4
lonoo in I si
1 up
I so
Dnmlioir
r-Soloo(od
ills'
WeiiilH
l"r;iolion''
'siriod
Room
of I so"
(horsill
( onfidonoo
\iiU)inoii\ e
AC Leak
Sealer
\eiosiil
High
High
Medium
Medium
iiigh
High
Medium u<
High
Automotive
AC
Refrigerant
Aerosol
High
High
Medium
Medium
High
High
Medium to
High
Adhesives
Liquid
High
High
High
High
High
Medium
High
Adhesives
Remover
Liquid
High
High
High
High
High
Medium
High
Brake Cleaner
Aerosol
High
High
High
High
High
High
High
Brush Cleaner
Liquid
High
High
Medium
Medium
High
Medium
Medium to
High
Carbon
Remover
Aerosol
High
High
High
High
High
High
High
Carburetor
Cleaner
Aerosol
High
High
High
High
High
High
High
Coil Cleaner
Aerosol
High
High
Medium
Medium
High
High
Medium to
High
Cold Pipe
Insulating
Spray
Aerosol
High
High
Medium
Medium
High
High
Medium to
High
Electronics
Cleaner
Aerosol
High
High
High
High
High
High
High
Engine
Cleaner
Aerosol
High
High
High
High
High
High
High
Gasket
Remover
Aerosol
High
High
High
High
High
High
High
Sealant
Aerosol
High
High
High
High
High
High
High
Weld Spatter
Protectant
Aerosol
High
High
Medium
Medium
High
High
Medium to
High
Confidence in Model Used considers whether model has been peer reviewed and whether model is applied in a
manner appropriate to its design and objective. The model used (CEM 2.1) has been peer reviewed, is publicly
available, and has been applied in a manner intended.
Confidence in Model Default Values considers default value data source(s) such as building and room volumes,
interzonal ventilation rates, and air exchange rates. These default values are all central tendency values (i.e., mean
or median values) sourced from EPA's Exposure Factors Handbook (EPA. 20.1.1a). The one default value with a
high-end input is the overspray fraction, which is used in the aerosol or spray scenarios and assumes a certain
percentage is immediately available for inhalation.
Page 224 of 753

-------
Consumer
Condition of
I so
loiiii
( onfidonee
in Model
I sod1
(onfidonoo
in Model
Delimit
\ ;dues:
(onfidonee in I ser-Seleeled \";iriod
Inputs1
Miiss
I sod4
I so
Dumlioir
Woif-hl
l"r;ielion''
Room
of I so"
()\ Ol'illl
( onfidonee
3Confidence in User-Selected Varied Inputs considers the quality of their data sources, as well as relevance of the
inputs for the selected consumer condition of use.
'Mass Used is primarily sourced from the U.S. EPA (1987). which received a high-quality rating during data
evaluation and has been applied in previous agency assessments. Automotive AC Leak Sealer mass used was
derived by directions on product.
5Use Duration is primarily sourced from U.S. EPA (1987). which received a high-quality rating during data
evaluation and has been applied in previous agency assessments.
6Weight fraction of methylene chloride in products is sourced from product SDSs, which were not reviewed as part
of systematic review but were taken as authoritative sources on a product's ingredients.
Room of use (zone 1 in modeling) is informed by responses in U.S. EPA (.1.987) which received a high-quality
rating during data evaluation, although professional judgment is also applied for some scenarios.
Table 2-123. Confidence in individual consumer conditions of use for dermal exposure
evaluations
('onsumor
Condition
of I so
l-'oi'in
(onfidonee
in Modol
Used1
Conridoneo
in Modol
IKTiiull
N'.iliios-
( onfidei
V.
Use
Dui'iilion4
oo in I sor-f
iried Inpuh
Woifihl
l"r;ielion;
ioloolod
Room of
I so'1
(hei'idl ( onfidonee
Adhesives
Liquid
Low to
Medium
High
High
High
Medium
Low to Medium
Adhesives
Remover
Liquid
Low to
Medium
High
High
High
Medium
Low to Medium
Automotive
AC Leak
Sealer
Aerosol
Low to
Medium
High
Medium
High
High
Low to Medium
Automotive
AC
Refrigerant
Aerosol
Low to
Medium
High
Medium
High
High
Low to Medium
Brake
Cleaner
Aerosol
Low to
Medium
High
High
High
High
Low to Medium
Brush
Cleaner
Liquid
Low to
Medium
High
Medium
High
Medium
Low to Medium
Carbon
Remover
Aerosol
Low to
Medium
High
High
High
High
Low to Medium
Carburetor
Cleaner
Aerosol
Low to
Medium
High
High
High
High
Low to Medium
Coil Cleaner
Aerosol
Low to
Medium
High
Medium
High
High
Low to Medium
Page 225 of 753

-------
Table 2-123. Confidence in individual consumer conditions of use for dermal exposure
evaluations
Cold Pipe
Insulating
Spray
Aerosol
Low to
Medium
High
Medium
High
High
Low to Medium
Electronics
Cleaner
Aerosol
Low to
Medium
High
High
High
High
Low to Medium
Engine
Cleaner
Aerosol
Low to
Medium
High
High
High
High
Low to Medium
Gasket
Remover
Aerosol
Low to
Medium
High
High
High
High
Low to Medium
Sealant
Aerosol
Low to
Medium
High
High
High
High
Low to Medium
Weld Spatter
Protectant
Aerosol
Low to
Medium
High
Medium
High
High
Low to Medium
Confidence in Model Used considers whether model has been peer reviewed and whether model is applied in a
manner appropriate to its design and objective. The model used (CEM 2.1) has been peer reviewed, is publicly
available, and has been applied in a manner intended.
Confidence in Model Default Values considers default value data source(s) such as surface area to body weight
ratios for the dermal contact area. These default values are all central tendency values (i.e., mean or median
values) sourced from EPA's Exposure Factors Handbook (EPA. 20.1.1a).
Confidence in User-Selected Varied Inputs considers the quality of their data sources, as well as relevance of the
inputs for the selected consumer condition of use.
4Use Duration is primarily sourced from U.S. EPA (1987). which received a hieh-aualitv ratine durine data
evaluation and has been applied in previous agency assessments.
5Weight fraction of methylene chloride in products is sourced from product SDSs, which were not reviewed as
part of systematic review but were taken as authoritative sources on a product's ingredients.
6Room of use (zone 1 in modeline) is informed bv responses in U.S. EPA (1987) which received a hieh-aualitv
rating during data evaluation, although professional judgment is also applied for some scenarios.
Page 226 of 753

-------
3 HAZARDS
3.1 Environmental Hazards
3.1.1	Approach and Methodology
During scoping and problem formulation, EPA reviewed potential environmental health hazards
associated with methylene chloride. EPA identified the following sources of environmental
hazard data: TSCA Work Plan Chemical Risk Assessment Methylene Chloride: Paint Stripping
Use CASRN 75-09-2 (U.S. EPA. 2014). Dichloromethane: Screening Information DataSet
(SIDS) Initial Assessment Profile (OECD. 2.011). Environmental Health Criteria 164 Methylene
Chloride (WHO. 1996a). Canadian Environmental Protection Act Priority Substances List
Assessment Report: Dichloromethane (Health Can a 3), and Ecological Hazard Literature
Search Results in Methylene Chloride (CASRN 75-09-2) Bibliography: Supplemental File for the
TSCA Scope Document (EPA-HQ-OPPT-2016-0742-0059) (U.S. EPA. 2.017a).
EPA completed the review of environmental hazard data/information sources during risk
evaluation using the data quality review evaluation metrics and the rating criteria described in the
Application of Systematic Review in TSCA Risk Evaluations (	'.018a). Studies were
assigned an overall quality level of high, medium, or low. The data quality evaluation results are
outlined in Supplemental File: Data Quality Evaluation of Environmental Hazard Studies (EPA.
2019r). With the data available, EPA only used studies with an overall quality level of high or
medium for quantitative analysis during data integration. Studies assigned an overall quality
level of low were used qualitatively to characterize the environmental hazards of methylene
chloride. Any study assigned an overall quality level of unacceptable was not used for data
integration.
3.1.2	Hazard Identification
Toxicity to Aquatic Organisms
EPA assigned an overall quality level of high, medium, or low to 14 acceptable studies,
including two studies submitted as "substantial risk" notifications under Section 8(e). These
studies contained relevant aquatic toxicity data for amphibians, fish, aquatic invertebrates, and
aquatic plants. EPA identified 11 aquatic toxicity studies, displayed in Table 3-1, as the most
relevant for quantitative assessment. The rationale for selecting these studies is provided in
Section 3.1.3 Weight of Scientific Evidence.
Aquatic Environmental Hazards from Acute Exposures to Methylene Chloride
Amphibians: Seven amphibian species were exposed to methylene chloride for up to five and a
half days in two flow-through studies, which EPA assigned an overall quality level of high
(Black et at.. 1982.; Birge et at.. 1980). Birge (1980) exposed embryos and larvae of Anaxyrus
fowleri (Fowler's toad, hatches in 3 days), Lithobatespalustris (pickerel frog, hatches in 4 days),
and Rana catesbeiana (American bullfrog, hatches in 4 days) to methylene chloride through 4
Page 227 of 753

-------
days post-hatch. Black (1982) tested Rana temporaria (common European frog, hatches in 5
days), Xenopus laevis (African clawed frog, hatches in 2 days), Lithobatespipiens (leopard frog,
hatches in 5 days), and Ambystoma gracile (Northwestern salamander) through 4 days post-
hatch. The concentration of methylene chloride lethal to half the population (median lethal
concentration, or LCso) of R catesbeiana embryos, exposed for 4 days, was 30.6 mg/L, and for
R. temporaria embryos exposed for 5 days was 23 mg/L (Biree et at.. 1980). Definitive LCsos
were not established for embryos of A. fowleri (> 32 mg/L), L. palustris (> 32 mg/L), X. laevis (>
29 mg/L), and L. pipiens (> 48 mg/L), which were exposed from 2 to 5 days to the highest
concentrations tested. The embryos of the Northwestern salamander, A. gracile, had an LCso of
23.9 mg/L after 5.5 days of exposure, similar to R. temporaria and R. catesbeiana (Black et at..
1982). However, because the exposure duration was a borderline sub-chronic value, and because
salamanders have a different biology (i.e., gill structure) from the frogs tested, EPA did not
integrate this hazard value with the frog results. The two amphibian studies demonstrate the
variation in amphibian species sensitivity to methylene chloride, with the bullfrog, R.
catesbeiana having the greatest sensitivity to the chemical substance. Both study authors
included embryo teratogenesis, which they defined as the percent of survivors with gross and
debilitating abnormalities likely to result in eventual mortality, into the LCso values and adjusted
for controls. EPA integrated the definitive LCso values fori?, temporaria (common European
frog) and R catesbeiana (American bullfrog) into a geometric mean of 26.3 mg/L (Black et at..
1982; Biree et at.. 1980).
Fish: EPA assigned an overall quality level of high to three acute (96-hr; flow-through) fish
toxicity studies, which evaluated the median lethal concentrations (LCsos) of methylene chloride
to Pimephalespromelas (fathead minnow) or Oncorhynchus mykiss (rainbow trout) (Dill et al..
1987;  j 1 *upont Denemours & Co Inc. 1987b; Geiger ci 3! i_5). EPA assigned one study
that used adult P. promelas obtained from a bait company with an overall quality level of
medium (Alexander et al.. 1978). Dill (1987) noted loss of equilibrium, a sub-lethal effect, in
juvenile P. promelas exposed to methylene chloride at concentrations > 357 mg/L for exposures
from 24 hours to test termination at 192 hours. The 96-hour LCso for fathead minnows was 502
mg/L. Alexander (1978) established an LCso of 193 mg/L for adult I', promelas exposed to
methylene chloride for 96 hours. The authors also reported an ECso of 99 mg/L for
immobilization in fathead minnows exposed to methylene chloride. The authors defined
immobilization as fish with loss of equilibrium, melanization, narcosis, and swollen,
hemorrhaging gills. E I Dupont Denemours & Co Inc (1987b) established a 96-hour LCso of 108
mg/L in O. mykiss. The authors observed rainbow trout exposed to methylene chloride
concentrations > 39 mg/L swimming at the surface, swimming erratically, and/or exhibiting
melanization. The 96-hr LCsos from the high and medium quality-level studies ranged from 108
mg/L to 502 mg/L. EPA integrated the acute 96-hour LCso values for hazard evaluation into a
geometric mean of 242.4 mg/L.
Aquatic Invertebrates: For freshwater aquatic invertebrates, EPA assigned two studies with
Daphnia magna (water flea) acute (48-hr ECso; static) exposures to methylene chloride with an
overall quality level of high ( )upont Denemours & Co Inc. 1987a; Leblanc. 1980). EPA
assigned one study on I), magna an overall quality level of medium (Abernethy et al.. 1986). and
one study an overall quality level of low (Kuhn et al.. 1989). The ECso values for the studies that
EPA assigned medium or high overall quality levels ranged from 135.8 mg/L to 177 mg/L for
Page 228 of 753

-------
48-hour exposures to methylene chloride. LeBlanc (1980) established a 48-hour LC50 of 176
mg/L. For aquatic invertebrates, EC50S and LC50S are calculated using the same methodologies
and integrated together, because mortality is difficult to distinguish from immobilization. EPA
integrated these hazard values into a geometric mean of 180 mg/L. LeBlanc (1980) also
established a no observed effect concentration (NOEC) for mortality in I). magna exposed to
methylene chloride concentrations of 54.4 mg/L for 48 hrs. This NOEC value is used to contrast
with the EC50S and LC50S as the concentration at which methylene chloride is not expected to
have an effect on aquatic invertebrates on an acute exposure basis.
EPA assigned one saltwater invertebrate (Palaemonetespugio, daggerblade grass shrimp) study
an overall quality level of high (Wilson. 1998). however, the authors did not provide a test
substance source or substance purity information. The authors reported up to a three-day
developmental delay for saltwater shrimp embryos exposed to 0.1 % v/v of methylene chloride
for 96-hrs, and complete developmental arrest for embryo and larvae exposed to > 0.5 % v/v for
96-hrs. However, the test concentrations were reported in percent volume to volume (% v/v), and
EPA could not accurately convert these values to weight per volume (mg/L) without making an
assumption about the test substance purity. Because the study could not be compared to other
data (i.e., freshwater invertebrates), it had lower relevance and, therefore, was not integrated into
the risk evaluation.
There were no aquatic sediment studies available for methylene chloride; however, EPA was
able to use a surrogate species to estimate toxicity. EPA considered using data on sediment
species from analogous chemicals, but no appropriate analogue with appropriate data was
identified for methylene chloride. Instead, because sediment organisms are expected to be
exposed to freely dissolved methylene chloride in the surface water or pore water, daphnids were
used as a surrogate species for estimating hazard in sediment invertebrates.
Aquatic Environmental Hazards from Subchronic and Chronic Exposures to Methylene
Chloride
Amphibians: There were no chronic studies that encompassed amphibian metamorphoses and
adult reproductive stages of the amphibian lifecycle. However, in the available, acceptable
studies, amphibian embryo and larvae were the most sensitive life stages to subchronic exposures
to methylene chloride in the aquatic environment. In the two studies by Birge (1980) and Black
(1982) that EPA assigned an overall quality level of high, the authors continued exposures of
embryos and larvae of seven amphibian species (A. fowleri, R catesbeiana, L. palustris, R.
temporaria, X. laevis, L. pipiens, and A. gracile) to methylene chloride for an additional 4 days
post-hatch under flow-through conditions. The study authors included teratogenic embryos and
larvae in mortality calculations to establish a 10% impairment value (LC10) and LC50 fori?.
catesbeiana (Birge et at.. 1980) and R temporaria (Black et al.. 1982) exposed for 8 days and 9
days to methylene chloride, respectively. At control-adjusted concentrations, the LC10 fori?.
catesbeiana was 1 mg/L, and the LC10 fori?, temporaria was 0.8 mg/L. The control-adjusted
LC50 fori?, catesbeiana embryo and larvae exposed for 8 days was 17.8 mg/L, and fori?.
temporaria embryo and larvae exposed for 9 days was 16.9 mg/L. Impairment values and
definitive LC50S were not established for embryos of A. fowleri, L. palustris, X. laevis, and L.
pipiens exposed for 6 to 9 days to the highest concentrations tested, because these species were
Page 229 of 753

-------
considerably more tolerant to exposures to methylene chloride. The authors determined a 9.5-day
LC50 of 17.8 mg/L for A. gracile, which is similar to the bullfrog and common frog hazard
values, but because salamanders have a different biology from frogs, EPA did not integrate the
data for A. gracile. A LC10 was not established for this species. EPA integrated the bullfrog and
common European frog LCios into a geometric mean of 0.9 mg/L, and their LC50S into a
geometric mean of 17.3 mg/L. EPA applied the acute-to-chronic ratio (ACR) of 10 to the
integrated acute amphibian larval toxicity value of 26.3 mg/L for the more protective LC50 value
of 2.6 mg/L.
Fish: In fish, there were two studies with chronic exposure aquatic toxicity data, an 0. mykiss
(rainbow trout) study with embryos and larvae exposed to methylene chloride under flow-
through conditions for up to 27 days (Black et at.. 1982.). and a study with P. promelas embryos
and larvae exposed for 32 days (Dill et at... 1987). Both authors also had sub-chronic toxicity
values fori5, promelas (fathead minnow). After 9 days of exposure to methylene chloride, the
minnow embryo and larvae (which hatched on day 4 of exposures) in the Black (1982) study had
LC50S > 34 mg/L, the highest concentration tested. In the chronic test with O. mykiss by Black
(1982). the LC50 for rainbow trout embryos exposed up to hatching at 23 days was 13.5 mg/L,
and the LC50 for larvae exposed up to four days post-hatch at 27 days was 13.2 mg/L. EPA
integrated the trout data into a geometric mean of 13.3 mg/L. The Black (1982) study also
indicated that there were no effects on survival of 0. mykiss larvae exposed to methylene
chloride at concentrations of 0.008 mg/L with survival decreasing to 85% at 0.4 mg/L, and 44%
at 23.1 mg/L. The authors did not establish that the decreased survival at 0.4 mg/L was
statistically significant, although survival data was adjusted for control mortalities. The authors
noted teratic larvae were observed at exposure concentrations of 5.5 mg/L (the next highest test
concentration) or greater. EPA considered the concentration of 0.4 mg/L as the NOEC for this
study, and 5.5 mg/L as the lowest observed effect concentration (LOEC), and integrated these
values into a geometric mean chronic toxicity value (ChV) for fish of 1.5 mg/L. P. promelas
juveniles exposed for 8-days in the Dill (1987) sub-chronic study had and LC50 of 471 mg/L. In
the Dill (1987) 32-day study, there was statistically significant reduction in larval survival at the
two highest concentrations tested, 209 and 321 mg/L, with 100% mortality within 96-hours post-
hatch at 321 mg/L, which EPA interpreted as the 8-day LC100 value fori5, promelas embryos and
larvae. The studies suggest that fathead minnow embryo and larvae are more sensitive to
methylene chloride exposures than juveniles. The 32-day no observed effect concentration
(NOEC) for mortality was 142 mg/L, and the lowest observed effect concentration (LOEC) for
mortality was 209 mg/L. EPA integrated the 32-day NOEC and LOEC for mortality into a
geometric mean, or maximum acceptable toxicant concentration (MATC) of 172.3 mg/L. Dill
(1987) established a NOEC of 82.5 mg/L and a LOEC of 142 mg/L for loss of body weight in P.
promelas exposed to methylene chloride, and a MATC of 108 mg/L from the geometric mean of
the NOEC and LOEC.
Aquatic Invertebrates: There were no acceptable chronic exposure aquatic invertebrate studies,
so EPA applied the acute to chronic ration (ACR) of 10 to the D. magna (water flea) acute
EC50/LC50 integrated geometric mean of 180 mg/L to estimate the freshwater aquatic
invertebrate chronic exposure toxicity value of 18 mg/L( upont Denemours & Co Inc.
1987a; Abernethy et at... 1986; Leblanc. 1980). In the absence of chronic exposure duration
studies for aquatic invertebrates, EPA also used ECOSAR v.2.0, the Agency's application for
estimating environmental hazards from industrial chemicals. ECOSAR classified methylene
Page 230 of 753

-------
chloride as a neutral organic, with a freshwater aquatic invertebrate ChV of 12 mg/L. ECOSAR
also estimated a saltwater mysid ChV of 41.8 mg/L, which also falls within range of the aquatic
invertebrate hazard value. The ECOSAR predicted ChVs support the freshwater invertebrate
chronic hazard value of 18 mg/L.
Aquatic Plants (Algae): For aquatic plants hazard studies, algae are the common test species.
Algae are cellular organisms which will cycle through several generations in hours to days,
therefore the data for algae was assessed together regardless of duration (i.e., 48-hrs to 96-hrs).
For algae, there were two studies (under static conditions) that EPA assigned an overall quality
level of high, a 72-hr exposure biomass inhibition in the green algae species Chlamydomonas
reinhardtii (Brack and Rattier. 1994) and a 96-hr biomass inhibition (characterized by the
authors as "the net production of algal cell density") study with the green algae
Pseudokirchneriella subcapitata (Tsai and Chen. 2007). The 96-hr EC 50 fori5, subcapitata
biomass inhibition was 33.1 mg/L, while the 72-hr EC50 for C. reinhardtii, was 242 mg/L. The
hazard value for C. reinhardtii is nearly an order of magnitude higher than the 96-hr EC50 fori5.
subcapitata. While it is likely the hazard value for C. reinhardtii would have decreased had the
study been extended to 96-hrs, the 72-hr EC 10 of 115 mg/L for 10% biomass inhibition in C.
reinhardtii established by Brack (1994) is higher than the 96-hr EC50 fori5, subcapitata. The
studies suggest that P. subcapitata, a static algal species that is an obligate phototroph, is more
sensitive to methylene chloride exposures relative to C. reinhardtii, a motile algal species with
two flagella that is a facultative heterotroph. In addition to the functional differences between the
two algal species, the study durations vary by 24 hours, in which time multiple generations of
algal cells would be produced. Therefore, the two hazard values were not integrated, and EPA
used the 96-hour EC50 of 33.1 mg/L for the more sensitive species, P. subcapitata, as the more
protective value to represent hazards to green algae as a whole.
In one study that EPA assigned an overall quality level of medium, growth was measured via
relative chlorophyll a absorbance in three green algae species, C. vulgaris, P. subcapitata, and
Volvulina steinii exposed to methylene chloride under static conditions for 10 days (Ando et al.
2003). The study did not have critical details, such as analytical measurement of test
concentrations, chemical substance source or purity, or an EC50 calculated from the relative
absorbance results. In addition, chlorophyll a is a pigment in the cells of algae that is an indirect
indicator of growth that EPA does not consider relevant for hazard evaluation of green algae.
Therefore, the study was not integrated into the environmental hazard calculation but is used
here qualitatively. There was no significant change in the relative absorbance of chlorophyll a
for C. vulgaris or P. subcapitata up to the highest nominal concentration tested, 2 mg/L.
However, methylene chloride killed V. steinii, a flagellar alga, at the lowest nominal
concentration tested, 0.002 mg/L. The authors attributed the variation in algal species sensitivity
to methylene chloride to V. steinii's high metabolism.
Page 231 of 753

-------
Table 3-1. Ecological Hazard Characterization of Methylene Chloride for Aquatic
Organisms	



llii/iii'd
(iCoiiH'li'ic



IVsl
I'lnripoini
Mlllll'S
Moiin1

( iliilion (l)iiiii r.\;iliiiiiion
Dui'iilion
or^iiiiism
(l"ivsh\\;i(cr)
(niii/l.)
(inii/1.)
IHTecl l.ndpoiiK
Killing)2


4 to 5-day





Amphibian
LC50
(frog
embryos &
larvae)
23 ->48
26.3
Teratogenesis
Leading to
Mortality
(Biree et al. 1980) (Hish);
(Black et al.. 1982) (Hiah)

5.5-day
LC50
(salamander
embryos &
larvae)
23.9

Teratogenesis
Leading to
Mortality
(Black et al. 1982) (Hish)
Acute

96-hour
EC50
(adults)
99

Immobilization3
(Alexander eta!.. 1.9781
(Medium)

Fish
96-hour
LC50
(juveniles
and adults)
108 - 502
242.4
Mortality
(Alexander et al, 1978)
(Medium); (Dill et al.. .1.987)
(Hish); (GeigeretaL .1.986)
(High); (EI Duponf Denemours
& Co Inc. 1987b) (Hieh)

Aquatic
48-hour
EC50/LC50
135.8 -
177
180
Immobilization
(Abernethv et al.. .1.986)
(Medium); ( pent
Denemours & Co Inc. 1987a)

Invertebrate



and Mortality
(High); (Lebtanc. .1.980) (High);


48-hr NOEC
54.4


(Leblanc. .1.980) (Hish)


8 to 9-day
(frog
embryos &
larvae)
LC10
LC50
0.8-1
16.9->
48
0.9
17.3
Teratogenesis
Leading to
Mortality
(Black et al.. .1.982) (Hieh);
(Biree et al. .1.980) (High)

Amphibian
4 to 5-day
LC50
2.6
(ACR10)
-


Subchronic

9.5-day




/Chronic

LC50
(salamander
embryos &
larvae)
17.8

Teratogenesis
Leading to
Mortality
(Black et al. 1.982) (Hish)

Fish
8-day
LC50
(juveniles)
LC100
(embryos &
larvae)
471
321

Mortality
(Pill et.aL 1987) (High)
Page 232 of 753

-------
Diii'iilion
Tesl
oi'^iiiiism
Kmlpoini
(l"ivsh\\;i(or)
Ihi/iinl
MllllC'S
(ii'oiiH'li'ic
Mciin1
(111 Si/I.)
l-llTccl l.ndpoinl
( iliilion (l)iilii l.\;ilu;i(ion
Killing


9-day
LC50
(embryo &
larvae)
>34

Teratogenesis
Leading to
Mortality
(Black et aL 1982) (Hiah)


23 to 27-day
LC50
(embryo &
larvae)
13.2-
13.5
13.3
Teratogenesis
Leading to
Mortality
(Black et a.L 1982) (Hish)


23 to 27-day
NOEC
LOEC
(embryo &
larvae)
0.4-5.5
1.5
Teratogenesis
(Black et al. 1982) (Hish)


32-day
NOEC
LOEC
(embryo &
larvae)
142
209
172.3
(MATC)
Mortality
(Dill et al. 1987) (Hish)


82.5
142
108
Growth (Body
Weight)






(Abernetlw et al, 1986)

Aquatic
invertebrate
48-hrs4
EC50/LC50
184

Immobilization
and Mortality
(Medium); ( Dont
Denemours & Co Inc. 1987a)





(Hish): (Leblanc. 1980) (Hish)
Algae
72-hour EC50
96-hour EC50
242
33.1

Biomass
(Tsai and Chen. 2007) (Hish);
(Brack and Rot tier, 1994)
(High);
(Ando et al. 2003)

EC10
115

Biomass
(Brack and Rottler. 1994) (Hish)
1	Geometric mean of definitive values only (i.e., > 48 mg/L was not used in the calculation).
2	While the hazard values are presented in ranges, the citations represent all of the data included in the range
presented.
3	Immobilization was reported by Alexander (1978) as loss of equilibrium, melanization, narcosis and swollen,
hemorrhaging gills.
4	EPA applied the ACR of 10 to the geometric mean of the integrated acute duration aquatic invertebrate studies.
3.1.3 Weight of Scientific Evidence
During the data integration stage of systematic review EPA analyzed, synthesized, and integrated
the data/information into Table 3-1. This involved weighing scientific evidence for quality and
relevance, using a weight-of-scientific-evidence approach, as defined in 40 CFR 702.33, and
noted in TSCA 26(i) (U.S. EPA. 2018aY
During data evaluation, EPA assigned studies an overall quality level of high, medium, or low
based on the TSCA criteria described in the Application of Systematic Review in TSCA Risk
Evaluations (U.S. EPA. 2018a). While integrating environmental hazard data for methylene
chloride, EPA gave more weight to relevant data/information that were assigned an overall
quality level of high or medium. Only data/information that EPA assigned an overall quality
Page 233 of 753

-------
level of high or medium was used for the environmental risk assessment. Data that EPA assigned
an overall quality level of low was used to provide qualitative characterization of the effects of
methylene chloride exposures in aquatic organisms. Any information that EPA assigned an
overall quality of unacceptable was not used. EPA determined that data and information were
relevant based on whether it had biological, physical/chemical, and environmental relevance
( ):
	Biological relevance: correspondence among the taxa, life stages, and processes
measured or observed and the assessment endpoint.
	Physical/chemical relevance: correspondence between the chemical or physical agent
tested and the chemical or physical agent constituting the stressor of concern.
	Environmental relevance: correspondence between test conditions and conditions in the
environment (	98).
EPA used this weight-of-evidence approach to assess hazard data and develop COCs. Given the
available data, EPA only used studies assigned an overall quality level of high or medium to
derive COCs for each taxonomic group. To calculate COCs, EPA derived geometric means for
each trophic level that had comparable toxicity values (e.g., multiple ECsos measuring the same
or comparable effects from various species within a trophic level). EPA did not use non-
definitive toxicity values (e.g., EC50 > 48 mg/L) to derive geometric means because these
concentrations of methylene chloride were not high enough to establish an effect on the test
organism.
To assess aquatic toxicity from acute exposures, data for three taxonomic groups were available:
amphibians, fish, and aquatic invertebrates. For each taxonomic group, adequate data were
available to calculate geometric means as shown in Table 3-1. The geometric mean of the LC50S
for amphibians, 26.3 mg/L, represented the most sensitive toxicity value derived from each of
the three taxonomic groups, and this value was used to derive an acute COC as described in
Section 3.1.4. This value is from two studies that EPA assigned an overall quality of high and
represents two species of amphibians. The geometric mean of ECsos/LCsos for aquatic
invertebrates, 180 mg/L, was used to derive an acute COC to use as a surrogate species hazard
value for sediment aquatic organisms. This geometric mean is from three studies that EPA
assigned an overall quality level of medium and high and represents one aquatic invertebrate
species.
To assess aquatic toxicity from chronic exposures, data for two taxonomic groups were described
in the acceptable literature: fish, and aquatic invertebrates. Because the most sensitive taxonomic
group from the acute data, amphibians, was not represented in the available chronic data, EPA
considered the acute hazard geometric mean of the LCios for amphibians for teratogenicity
leading to mortality to estimate chronic hazard values for amphibians. When comparing these
values to the other chronic data from fish and aquatic invertebrates, amphibians were again the
most sensitive taxonomic group. Therefore, the amphibian ChV of 0.9 mg/L was used to derive a
chronic COC in Section 3.1.4. This value was from two studies that EPA assigned an overall
quality level of high and represents two species of amphibians. For comparison, EPA calculated
a ChV for fish of 1.5 mg/L for teratogenesis from a study that EPA assigned an overall quality
level of high, representing one species.
Page 234 of 753

-------
To assess the toxicity of methylene chloride to algae, data for two species were available from
studies that EPA assigned an overall quality level of high. EC50s measuring biomass inhibition
ranged from 33.1 mg/L to 242 mg/L, and an EC10 of 115 mg/L was also reported. The exposure
durations for the two tests differed by 24 hours, and the two algal species were functionally
different, so EPA used the EC50 for biomass inhibition from the more sensitive species to
represent algae as a whole. This value, 33.1 mg/L, from one high quality algae study
representing one species, was used to derive an algae COC in Section 3.1.4.
Based on the estimated bioconcentration factor and bioaccumulation potential described in
Section 2.1, methylene chloride does not bioaccumulate in biological organisms. Therefore, EPA
did not assess hazards to aquatic species from trophic transfer and bioconcentration or
accumulation of methylene chloride.
3.1.4 Concentrations of Concern (COC)
EPA calculated the COCs for aquatic species based on the environmental hazard data for
methylene chloride, using EPA methods (EPA. 2013b. 2012b). While there were data
representing amphibians, fish, aquatic invertebrates, and aquatic plants, the data were not robust
enough to conduct a more detailed species sensitivity distribution analysis. Therefore, EPA chose
to establish COC as protective cut-off standards above which acute or chronic exposures to
methylene chloride are expected to cause effects for each taxonomic group in the aquatic
environment. The COC is typically based on the most sensitive species or the species with the
lowest toxicity value reported in that environment. For methylene chloride, EPA derived an
acute and a chronic COC for amphibians, which represent the most sensitive taxonomic group to
methylene chloride exposure. Because other chronic toxicity data were relatively close to the
amphibian data, EPA also calculated a chronic COC for fish, and a chronic COC for aquatic
invertebrates for comparison. An algal COC was also calculated. Algae was assessed separately
and not incorporated into acute or chronic COCs, because durations normally considered acute
for other species (e.g., 48, 72 hrs) can encompass several generations of algae.
After weighing the scientific evidence and selecting the appropriate toxicity values from the
integrated data to calculate acute, subchronic/chronic, and algal COCs, EPA applied an
assessment factor (AF) according to EPA methods (EPA. 2013b. 2012b). when possible. The
application of AFs provides a lower bound effect level that would likely encompass more
sensitive species not specifically represented by the available experimental data. AFs can also
account for differences in inter- and intra-species variability, as well as laboratory-to-field
variability. These AFs are dependent on the availability of datasets that can be used to
characterize relative sensitivities across multiple species within a given taxa or species group.
However, they are often standardized in risk assessments conducted under TSCA, since the data
available for most industrial chemicals are limited. For fish and aquatic invertebrates (e.g.,
daphnia) the acute COC values are divided by an AF of 5. EPA does not have a standardized AF
for amphibians. For amphibians, there may be more uncertainty in the subchronic studies,
necessitating a more protective AF of 10. For chronic COCs, an AF of 10 is used. The COC for
the aquatic plant endpoint is determined based on the lowest value in the dataset and application
of an AF of 10 (EPA. 2013b. 2012bY
Page 235 of 753

-------
After applying AFs, EPA converts COC units from mg/L to |ig/L (or ppb) in order to more easily
compare COCs to surface water concentrations during risk characterization.
Acute COC
To derive an acute COC for methylene chloride, EPA used the geometric mean of the LCsos for
amphibians, which is the most sensitive acute value for aquatic species from the data integrated
for methylene chloride, from two studies EPA assigned overall quality levels of high (Black et
at.. 1982; Birge _ 3). The geometric mean of 26.35 mg/L was divided by the AF of 10
for amphibians and multiplied by 1,000 to convert from mg/L to |ig/L, or ppb.
The acute COC = (26.3 mg/L) / AF of 10 = 2.63 mg/L x 1,000 = 2,630 |ig/L or ppb.
	The acute COC for methylene chloride is 2,630 ppb.
EPA used aquatic invertebrate hazard values as surrogate species to address hazards to sediment
invertebrates. EPA derived an acute COC from the geometric mean of the ECsos and LCsos from
two Daphnia magna studies that EPA assigned an overall quality level of high (E I Dupont
Denemours & Co Ii 7a; Leblanc. 19801 and one study that EPA gave an overall quality
levels of medium (Abernethy et at.. 1986). The geometric mean of 180 mg/L was divided by the
AF of 5 and multiplied by 1,000 to convert from mg/L to |ig/L, or ppb.
The acute aquatic invertebrate COC = (180 mg/L) / AF of 5 = 36 mg/L x 1,000 = 36,000 |ig/L or
ppb.
	The acute aquatic invertebrate COC for methylene chloride is 36,000 ppb.
Chronic COC
EPA derived the amphibian chronic COC from the lowest chronic toxicity value from the
integrated data, the amphibian geometric mean of LCio for developmental effects and mortality
in common frogs and American bullfrogs in two studies EPA assigned overall quality levels of
high (Stack et at.. 1982; Birge et at.. 1980). The LCio was then divided by an assessment factor
of 10, and then multiplied by 1,000 to convert from mg/L to |ig/L, or ppb.
The chronic COC = (0.9 mg/L) / AF of 10 = 0.09 mg/L x 1,000 = 90 |ig/L or ppb.
 The amphibian chronic COC for methylene chloride is 90 ppb.
EPA also derived a chronic COC for fish and aquatic invertebrates for comparison to the
amphibian chronic data. The fish chronic COC was derived from the most sensitive chronic
toxicity value from the integrated data, the ChV measuring teratogenesis in rainbow trout from a
study that EPA assigned a quality level of high (Stack et at.. 1982). The ChV was then divided
by an assessment factor of 10, and then multiplied by 1,000 to convert from mg/L to |ig/L, or
ppb.
The chronic COC = (1.5 mg/L) / AF of 10 = 0.15 mg/L x 1,000 = 150 |ig/L or ppb.
Page 236 of 753

-------
	The fish chronic COC for methylene chloride is 150 ppb.
To derive a chronic COC for aquatic invertebrates, EPA used the toxicity value derived from the
integrated acute toxicity data, the geometric mean of 180 mg/L, calculated from data on the
freshwater invertebrate species, Daphnia magna. EPA applied the acute-to-chronic ratio of 10,
resulting in a chronic aquatic invertebrate ChV of 18 mg/L. This ChV was then divided by an AF
of 10 and multiplied by 1,000 to convert mg/L to |ig/L, or ppb.
The chronic COC for aquatic invertebrates = (18 mg/L) / AF of 10 = 1.8 mg/L x 1,000 = 1,800
|ig/L or ppb.
	The aquatic invertebrate chronic COC for methylene chloride is 1,800 ppb.
Algal COC
The algal COC was derived from the hazard value for the static algae Pseudokirchneriella
subcapitata from one study that EPA assigned an overall quality level of high (Tsai and Chen.
2007). This algal species was selected as the more sensitive species from the available data to
represent algal species as a whole. The 96-hour ECso for biomass inhibition of 33.1 mg/L was
divided by an assessment factor of 10, and then multiplied by 1,000 to convert from mg/L to
|ig/L, or ppb.
The algal COC = (33.1 mg/L) / AF of 10 = 3.31 mg/L x 1000 = 3,310 |ig/L or ppb.
	The algal COC is 3,310 ppb.
3.1.5 Summary of Environmental Hazard
EPA concludes that acute exposures to methylene chloride present hazards for amphibians, with
toxicity values ranging from 23 mg/L to > 48 mg/L, integrated into a geometric mean of 26.3
mg/L from the definitive hazard values for two frog species (based on teratogenesis leading to
lethality in embryos and larvae). Acute exposures to methylene chloride also present hazards for
fish, with an immobilization hazard value of 99 mg/L in adult fish. Juvenile and adult fish
mortality hazard values from acute exposures ranged from 108 to 502 mg/L, and EPA integrated
these values into a geometric mean of 242.4 mg/L. For freshwater aquatic invertebrates, acute
exposure hazard values for immobilization and mortality ranged from 135.8 mg/L to 177 mg/L,
integrated into a geometric mean of 180 mg/L.
For chronic exposures, methylene chloride presents a hazard to amphibians, with toxicity values
ranging from 0.8 to > 48 mg/L. The lowest chronic hazard values for amphibians, 0.8 mg/L and
1 mg/L, for teratogenesis and lethality in embryos and larvae of two frog species, integrated into
a geometric mean of 0.9 mg/L. For chronic exposures, methylene chloride also presents a risk to
fish, with hazard values ranging from 0.4 to 209 mg/L for teratogenesis, teratogenesis leading to
Page 237 of 753

-------
mortality, mortality, and growth inhibition. EPA assessed a NOEC and LOEC of 0.4 mg/L and
5.5 mg/L, respectively, for fish larvae mortality in one study, and integrated these hazard values
into a geometric mean of 1.5 mg/L. There were no chronic duration hazard data for aquatic
invertebrates, so EPA applied the acute-to-chronic ratio of 10 to the acute exposure aquatic
invertebrate hazard value of 180 mg/L, resulting in a chronic exposure hazard value for aquatic
invertebrates of 18 mg/L. For algae, hazard values for exposures to methylene chloride from two
algal species were 33.1 mg/L and 242 mg/L. The hazard value for the more sensitive green algae
species, 33.1 mg/L, is used to represent algal species as a whole.
Concentrations of Concern (COC):
The acute and chronic COCs derived for aquatic organisms are summarized in Table 3-2. EPA
calculated the acute COC for methylene chloride exposures in amphibians as 2,630 ppb, based
on the geometric mean of LCsos for amphibians from two studies that EPA assigned an overall
quality level of high (Black et ai. 1982.; Btree et at.. 1980). EPA also calculated an acute aquatic
invertebrate COC of 36,000 ppb, to address sediment invertebrate hazards. EPA calculated the
chronic COC for methylene chloride in amphibians as 90 ppb, based on the chronic toxicity
value derived from the geometric mean of the LCio.
For comparison with other trophic levels, EPA calculated a fish chronic COC of 151 ppb, based
on a geometric mean of a NOEC and LOEC from a study measuring teratogenesis in rainbow
trout that EPA assigned a quality level of high (Black et at.. 1982). EPA also calculated an
aquatic invertebrate chronic COC for methylene chloride of 1,800 ppb, based on the geometric
mean of ECsos and LCsos from aquatic invertebrate studies that EPA assigned overall quality
levels of medium and high. As noted previously, algal hazard values from exposures to
methylene chloride, for durations ranging from 48 hrs to 96 hrs are considered separately from
other aquatic species, because algae can cycle through several generations in this time frame.
The algal COC of 3,310 ppb is based on the lowest ECso value for one study that EPA assigned
overall quality levels of high.
The embryos and larvae of amphibians were the most sensitive organisms to acute exposures to
methylene chloride, whereas adult fish and aquatic invertebrates had hazard values roughly an
order of magnitude higher. For chronic exposures, the embryos and larvae of amphibians again
had the most sensitive hazard values, followed closely by the embryos and juveniles of fish.
Chronic hazard values for aquatic invertebrates and hazard values for algae were at least an order
of magnitude higher than for the amphibian and fish embryos and larvae.
Page 238 of 753

-------
Table 3-2. COCs for Environmental Toxicity
Knvironnienlal Aquatic Toxicity
Hazard Value
(MS"-)
Assessment
l-'actor
(()<
(u/l. or pph)
Toxicity to Amphibians from Acute
Exposures
26,300
10
2,630
Toxicity to Aquatic Invertebrates from
Acute Exposures
179,980
5
36,000
Toxicity to Amphibians from Chronic
Exposures
900
10
90
Toxicity to Fish from Chronic
Exposures
1,510
10
151
Toxicity to Aquatic Invertebrates from
Chronic Exposures
18,000
10
1,800
Algal Toxicity
33,100
10
3,310
3.2 Human Health Hazards
3.2.1 Approach and Methodology
EPA used the approach described in Figure 3-1 to evaluate, extract and integrate methylene
chloride's human health hazard and dose-response information. This approach is based on the
Application of Systematic Review in TSCA Risk Evaluations (	1018a) and the
Framework for Human Health Risk Assessment to Inform Decision Making (EPA. 2014a).
Page 239 of 753

-------
Data
Summaries for
Adverse
Endpoints
(Supplemental
Human Health
Document)
Risk Characterization
Human Health Hazard Assessment
Data Evaluation
After full-text screening,
apply pre-determined data
quality evaluation criteria
to assess the confidence of
key and supporting studies
identified from previous
assessments as well as
new studies not
considered in the previous
assessments
	Uncertainty and variability
	Data quality
	PESS
	Alternative interpretations
Risk Characterization
Analysis
Determine the qualitative
and/or quantitative human
health risks and include, as
appropriate, a discussion of:
Data Integration
Integrate hazard information by considering quality (i.e.5
strengths, limitations), consistency, relevancy, coherence and
biological plausibility
Hazard ID
Confirm potential
hazards identified
during
scoping/problem
formulation and
identify new hazards
from new literature (if
applicable)
Dose-Response
Analysis
Benchmark dose
modeling for
endpoints with
adequate data;
Selection of PODs
Output of
Systematic
Review
Stage
WOE
Narrative by
Adverse
Endpoint
(Section 3.2.4)
Summary of
Results and
PODs
(Section 3.2.5)
Risk Estimates
and
Uncertainties
(Section 4.2)
Figure 3-1. EPA Approach to Hazard Identification, Data Integration, and Dose-Response
Analysis for Methylene Chloride
Specifically, EPA reviewed key and supporting information from previous hazard assessments as
well as the existing body of knowledge on methylene chloride's human health hazards, which
includes information published after these hazard assessments. The previous hazard assessments
consulted by EPA include the following:
	Spacecraft Maximum Allowable Concentrations (SMAC) for Selected Airborne
Contaminants: Methylene chloride (Volume 2) published by the U.S. National Academies
(Nrc. 1996);
	OSHA Final Rides, Occupational Exposure to Methylene Chloride by the Occupational
Health and Safety Administration (OSHA 1997a);
	Toxicological Profile for Methylene Chloride by the Agency for Toxic Substances
Disease Registry (ATSDR. 2000);
	Interim Acute Exposure Guideline Levels (AEGLs) for Methylene Chloride developed by
the U.S. NAC on AEGLs (Nrc. 2008);
	Acute Reference Exposure Level (REL) and Toxicity Summary for Methylene Chloride
published by the California Office of Environmental Health Hazard Assessment (Oehha.
2008a);
	Toxicological Review of Methylene Chloride published in 2011 by EPA's IRIS (U.S.
EPA. 2011); and
	TSCA Work Plan Risk Assessment, Methylene Chloride: Paint Stripping Use (U.S. EPA.
2014).
The health hazards of methylene chloride previously identified in these reviews were described
and reviewed in this risk evaluation, including acute toxicity, neurotoxicity, liver toxicity,
immunotoxicity, reproductive/ developmental toxicity, irritation/burns and genotoxicity/
Page 240 of 753

-------
carcinogenicity. EPA relied heavily on the aforementioned existing reviews along with scientific
support from the Office of Research and Development (ORD) in preparing this risk evaluation.
Development of the methylene chloride hazard and dose-response assessments considered EPA
and NRC risk assessment guidance.
In addition to the primary literature cited in these previous assessments, EPA also conducted a
search of newer literature to obtain information on all health domains. This process is outlined in
Section 1.5. For human health hazard data, EPA obtained peer reviewed studies published from
January 1, 2008 through March 2, 2017. EPA also obtained studies published after March 2017
that were identified by peer reviewers and public comments. Finally, EPA searched the gray
literature, particularly studies submitted under certain sections of TSCA; some of these studies
may have older dates (e.g., 1970s) but were still considered if they were not referenced in
previous assessments.
The new literature was screened against inclusion criteria within the PECO statement. Relevant
animal studies (i.e., potentially useful for dose-response) were further evaluated for data quality
using criteria for animal studies described in Application of Systematic Review in TSCA Risk
Evaluations (U.S. EPA. 2018a). Epidemiological studies were evaluated using Systematic
Review Supplemental File: Updates to the Data Quality Criteria for Epidemiological Studies
(EPA. 2019a). Because the key and supporting studies were considered in previous peer
reviewed assessments to be studies useful and relevant for hazard identification, EPA skipped the
screening step of the key and supporting studies and entered them directly into the data
evaluation step based on their relevance to the risk evaluation.
For methylene chloride, the chosen key and supporting studies were initially identified as those
used as the basis of acute values (California REL, SMAC, AEGLs and ATSDR minimum risk
levels (MRLs)) and those from the IRIS assessment considered for the derivation of the
inhalation reference concentration (RfC) and oral reference dose (RfD) as well as the suite of
animal cancer bioassays that evaluated liver and lung tumors in addition to other tumor types that
match those evaluated in recent epidemiology studies. In some cases, EPA expanded this list of
studies reviewed to support the hazard assessment for a particular endpoint. For example, EPA
evaluated the quality of all epidemiological studies that examined cancer endpoints to determine
differences in quality and to understand patterns among the study results. Section 3.2.3 describes
what was evaluated for data quality for each of the health domains.
EPA has not yet developed data quality criteria for all types of hazard information. For example,
data quality criteria have not been developed for toxicokinetics and many types of mechanistic
data that EPA typically uses for qualitative support when synthesizing evidence. Despite the lack
of formal criteria, for methylene chloride, EPA qualitatively evaluated and summarized data
(e.g., from human controlled experiments) if they were considered for the dose-response analysis
or to determine their utility in supporting the risk evaluation.
Following the data quality evaluation, EPA extracted the toxicological information from each
acceptable study into summary tables that include the endpoints considered for this assessment,
the no-observed- or lowest-observed-adverse-effect levels (NOAEL and LOAEL) for non-cancer
health endpoints by target organ/system, the incidence for cancer endpoints, and the overall data
Page 241 of 753

-------
quality evaluation ratings. The key/supporting studies and the newly identified studies found
through searching recent literature are identified. Risk Evaluation for Methylene Chloride,
Systematic Review Supplemental File: Data Extraction of Human Health Hazard Studies (EPA.
2019(a) presents these tables.
Section 3.2.3 (Hazard Identification) discusses the body of studies for relevant health domains.
EPA considered studies of low, medium or high confidence for hazard identification and focused
on the following health domains considered relevant for methylene chloride: acute toxicity,
neurotoxicity, liver toxicity, immunotoxicity, reproductive/ developmental toxicity, irritation and
genotoxicity/carcinogenicity. Information from studies that were rated unacceptable were only
discussed on a case-by-case basis for hazard identification and weight of scientific evidence
assessment but were not considered for dose-response analysis. In some cases, additional studies
not evaluated were also described within the hazard identification section as described in the
health domain specific sections.
The weight of scientific evidence analysis (Section 3.1.3) included integrating information from
toxicokinetic and toxicodynamic studies for the health domains described in Section 3.2.3. In
particular, data integration considered consistency among the data, data quality, biological
plausibility and relevance (although this was also considered during data screening). For each
health domain, EPA determined whether the body of scientific evidence was adequate to
consider the domain for dose-response modeling.
As presented in Section 3.2.5. (Dose-Response Assessment), data for the health domains with
adequate evidence were modeled to determine the dose-response relationships (Appendix I and
U.S. EPA (2019fa)u). For the relevant health domains, EPA considered points of departure
(POD) from studies that were PECO relevant, scored acceptable in the data quality evaluation
and contained adequate dose-response information. For methylene chloride, studies used for
dose-response modeling received high or medium quality ratings from the following health
domains: acute toxicity (based on neurotoxicity), non-cancer liver toxicity and
genotoxi city / carcinogeni city.
The POD is used as the starting point for subsequent dose-response (or concentration-response)
extrapolations and analyses. PODs can be aNOAEL, a LOAEL for an observed incidence, or
change in level of response, or the lower confidence limit on the benchmark dose (BMD)12. The
BMD analysis is discussed in Appendix I and the Risk Evaluation for Methylene Chloride,
Supplemental File - Methylene Chloride Benchmark Dose and PBPK Modeling Report (EPA.
2019h). PODs were adjusted as appropriate to conform to the specific exposure scenarios
evaluated (see Sections 3.2.5 and 4.3).
Inhalation acute human controlled experimental data and inhalation repeat-dose toxicity studies
in animals were available for methylene chloride and were considered for dose-response
assessment. No acceptable toxicological data are available by the dermal route. Furthermore, a
11 Risk Evaluation for Methylene Chloride - Methylene Chloride Benchmark Dose and PBPK Modeling Report
The BMD is a dose or concentration that produces a predetermined change in response range or rate of an adverse
effect (called the benchmark response or BMR) compared to baseline.
Page 242 of 753

-------
physiologically-based pharmacokinetic/pharmacodynamic (PBPK/PD) model that would
facilitate route-to-route extrapolation to the dermal route has not been identified for methylene
chloride. Therefore, inhalation PODs were extrapolated for use via the dermal route using
models that incorporate volatilization, penetration, absorption and a permeability coefficient
from an in vitro study in pig skin (Schenk et at.. 2018) as described in both Section 2.4.2.3.1 and
Risk Evaluation for Methylene Chloride (Dichlorome thane, DCM) CASRN: 75-09-2,
Supplemental Information on Releases and Occupational Exposure Assessment (EPA. 2019b).
EPA considered studies conducted via the inhalation route for this extrapolation for two primary
reasons. First, these studies are already being used to calculate risks from inhalation in the
current risk evaluation. Second, for cancer, the toxic moieties are metabolites of methylene
chloride and both the inhalation and dermal routes are similar due to the fact that neither route
includes a first pass through the liver (and subsequent metabolism) before entering the general
circulation whereas first pass metabolism is important for the oral route. The PODs estimated
based on effects in adult animals were converted to Human Equivalent Concentrations (HECs)
for inhalation studies and Human Equivalent Doses (HEDs) when converting to the dermal route
using species-specific PBPK models.
3.2.2 Toxicokinetics
Methylene chloride is quickly absorbed through inhalation exposure in humans and animals
(ATSDR. 2000). Pulmonary uptake ranges between 40 and 60 percent (Andersen et at.. 1991;
Stewart et at.. 1976; Gamberate et at.. 1975). but may be up to 70 percent during the first minutes
of exposure (Riley et at.. 1966). In humans, uptake decreases as exposure duration and
concentration increase (Peterson. 1978; Stewart et at.. 1976). A steady-state absorption rate is
generally achieved within 2 hrs for exposures up to 200 ppm in humans (Divincenzo and Kaplan.
1981; Divincenzo et at.. 1972.). One in vitro study (Schenk et at.. 2018) using pig skin measured
the dermal permeability of methylene chloride and estimated permeability coefficients of 8.66 x
10"3 cm/hr for the neat (100%) compound and 3.15 x 10"2 (1%) cm/hr for a 1% solution.
Information from this study is used in the risk evaluation to estimate dermal absorption.
Methylene chloride is rapidly distributed throughout the body, including the liver, brain and
subcutaneous adipose tissue, as identified in animal studies ('__> Jj	i, \ 1 ? <>R. 2000;
C art sson and Hut ten gren.. 1975). Among fatality cases, the highest concentrations were usually
found in the brain, then liver or kidneys and finaly in the lungs and heart (Nac/Aeel 2.008b).
Metabolism occurs predominantly in the liver, with additional transformation in the lungs and
kidneys (ATSDR. 2000). In the liver, two primary pathways are involved in the metabolism of
methylene chloride. The cytochrome P450 (CYP450) mixed function oxidase (MFO) pathway
(via CYP2E1) produces CO and C02, and saturation occurs at approximately 400-500 ppm after
inhalation exposure in humans (	). The CO metabolite reacts with hemoglobin to
form carboxyhemoglobin (COHb) ( DR. 2000).
The second pathway operates via glutathione S-transferase (GST); individuals with the theta 1
isozyme (GSTT1) metabolize methylene chloride to form formaldehyde and formic acid. In
animals, saturation occurs at >10,000 ppm after inhalation exposure. Methylene chloride binds to
the CYP reaction site with higher affinity than the GST site and COHb levels resulting from
Page 243 of 753

-------
methylene chloride's metabolism to CO can continue to increase and can reach peak levels 5 to 6
hours after exposure ( DR. 2000). Figure 3-2 outlines the biotransformation pathways for
methylene chloride.
Major differences in affinity or other aspects of the CYP450 MFO pathway among species have
not been identified (Nac/Aegl. 2008b). Studies generally indicate a 3- to 7-fold range in CYP2E1
activity among humans based on a variety of measures, with some research suggesting up to a
25-fold difference (	).
Comparing metabolism of methylene chloride by the GST pathway in liver and lung tissues
among species, mice are more active than rats, humans and hamsters (U.S. EPA. 2011).
Similarly, Thier et al. (1998) cited by U.S. EPA (	) found species" specific liver
GSTT1 isozyme activity after methylene chloride exposure to be ordered as follows (from
highest to lowest): mice, rats, human high conjugators, human low conjugators, hamsters and
human non-conjugators. Thier et al. (1998) cited by U.S. EPA (U.S. EPA. 2011) also reported
that high and low human conjugators exhibited GSTT1 activities in erythrocytes approximately
11 and 16 times higher than the human liver activities of high and low conjugators, respectively.
Furthermore, the human high conjugator GSTT1 activity in erythrocytes was the same as male
mouse liver activity and 61% of the female mouse liver activity. Among humans, the percent of
GSTT1 +/+ individuals is 32%, whereas GSTT1 +/- individuals represent 48% and GSTT1 -/-
individuals are 20% of the population (Haber et al.. 2002).
The plasma half-life is estimated to be 40 minutes after inhalation exposure by human subjects
(ATSDR. 2000; Divincenzo et al.. 1972). Unmetabolized methylene chloride is eliminated
primarily through the lungs. Urine and feces also contain small quantities of unchanged
methylene chloride (ATSDR. 2000). At low doses, a large percent of methylene chloride is
transformed into COHb and eliminated as CO. At higher doses, more of the unchanged parent
compound is exhaled (ATSDR. 2000).
Fetuses, infants and toddlers may be exposed to methylene chloride through breastfeeding and
placental transfer. Methylene chloride has been detected in human breast milk ((Pellizzari et al..
1982; Erickson et al.. 1980) and Vosovaja et al. (1974) as cited in Jensen (1983)). For example,
mean concentrations of methylene chloride in breast milk for Soviet women workers who
manufacture rubber articles were 74  46 ppb in 17 of 28 samples (specimens with detectable
levels) taken 5  7 hours after the start of work, with levels declining after termination of work
(Vosovaja et al. (1974) as cited in Jensen (1983)). Among babies born in 2015, the CDC 2018
breastfeeding report card found that the majority of newborns were breastfed. At 3 months,
approximately half of old infants were exclusively ingesting breastmilk, and at 12 months,
approximately a third were breastfed (https://www.cdc.gov/media/releases/2018/p0820-
breastfeeding-report-card.html).
Methylene chloride can also cross the placental barrier and enter fetal circulation, with some
research suggesting 2 to 2.5-fold lower concentrations in fetal blood, and other research
identifying similar CO levels (	).
Page 244 of 753

-------
Blood concentrations of methylene chloride were lower than the detection level in 2,878
individuals who participated in the National Health and Nutrition Examination Survey
(NHANES) based on subsamples of the U.S. population taken from the years 2009 and 2010
(CDC. 2019). Methylene chloride was found in the urine of workers employed at a
pharmaceutical factory during a four-hour work-shift but was nearly eliminated during the
overnight period following exposure (Hsdb. 2012).
CHiQi		* OCHC1 	* CO
f >T . 1 . * >.-<*
~	* CS'IT
Hh-v i k	?+ C3SH
i
	i
' : II
I	liicr:., .J..  
A ' i
HCOOH
T	i
1
GS-CHO
II.' M If;
formic miti
cm
Figure 3-2. Biotransformation Scheme of Methylene Chloride (modified after Gargas et al.,
1986).
Source: NAC/AEGL (2008b)
3.2.3 Hazard Identification
The methylene chloride database includes epidemiological studies, animal studies and in vitro
studies. Epidemiological studies, animal studies and human experimental studies examined
associations between methylene chloride exposure and multiple non-cancer effects and several
types of cancer. Human controlled experiments also evaluated non-cancer effects from
acute/short-term exposure. The following sections also describe several in vitro and some animal
studies that evaluated biochemical and other endpoints used to consider the evidence related to
modes of action.
EPA considered many of the studies as informative and useful for characterizing the health
hazards associated with exposure to methylene chloride. EPA extracted the results of key and
supporting studies from previous assessments and studies identified in the updated literature
search into tables included in Risk Evaluation for Methylene Chloride, Systematic Review
Page 245 of 753

-------
Supplemental File: Data Extraction of Human Health Hazard Studies (EPA. ). Several
sections within Section 3.2.3 contain tables of data for given health domains.
Supplemental files contain data evaluations of these studies, including study strengths and
limitations:
	Risk Evaluation for Methylene Chloride, Systematic Review Supplemental File: Data
Quality Evaluation of Human Health Hazard Studies - Epidemiological Studies (EPA.
20J9s);
	Risk Evaluation for Methylene Chloride, Systematic Review Supplemental File: Data
Quality Evaluation of Human Health Hazard Studies - Human Controlled Experiments
(EPA. 2019ft: and
	Risk Evaluation for Methylene Chloride, Systematic Review Supplemental File: Data
Quality Evaluation of Human Health Hazard Studies - Animal and In Vitro Studies
(EPA. 201911)
The weight of scientific evidence section (3.1.3) identifies any study evaluation concerns that
may have meaningfully influenced the reliability or interpretation of the results. Studies
considered for dose-response assessment are discussed in Section 3.2.5.
3,2,3,1 Non-Cancer Hazards
EPA reviewed the scientific literature on non-cancer hazards of methylene chloride, based on
systematic approaches described in Sections 1.5 and 3.2.4.1 and as presented in supplemental
materials (\ PA_ ^019s. t, u). As a result of this review, EPA identified six adverse health effect
domains: effects from acute/short-term exposure, liver effects, immune system effects, nervous
system effects, reproductive/ developmental effects and irritation/burns. The following sections
present data specific to each of these domains.
3.2.3.1.1 Toxicity from Acute/Short-Term Exposure
Neurotoxicity and neurological effects were the most frequently observed outcomes in the
available acute and short-term studies. Furthermore, acute lethality in humans following
inhalation relates to CNS depressant effects, which include loss of consciousness and respiratory
depression resulting in irreversible coma, hypoxia and eventual death (Nac/Aeel 2008b). Animal
studies have also primarily identified CNS effects in acute exposure studies.
Although human and animal studies have identified other effects (including immunosuppression,
liver effects, cardiac toxicity), the endpoints are observed either less often or at air concentrations
higher than those associated with CNS effects.
For the current risk evaluation, EPA relied on the human controlled experiments and used a
single study (Putz et al. 1979) that identified CNS effects. The following sections describe: 1)
human acute controlled experimental studies and case reports of fatalities or high exposures; 2)
acute exposure animal studies; and 3) the continuum of potential neurological effects, CNS
depression, other severe effects including death.
Humans
Page 246 of 753

-------
Several of the acute human experimental studies resulting in CNS-related effects form the basis
of acute exposure values such as the Spacecraft Maximum Allowable Concentration for Selected
Airborne Contaminant (SMAC) (Nrc, 1996). Acute Exposure Guideline Levels (AEGLs) 1 and
21S (Nac/Aegl. 2008b) and the California Reference Exposure Level (REL) (Oehha. 2008a). EPA
qualitatively reviewed these and other studies identified through backwards searching, drawing
upon components developed for the formal human epidemiological and animal toxicity data
quality criteria developed under TSCA. See Risk Evaluation Methylene Chloride, Systematic
Review Supplemental File: Data Quality Evaluation of Human Health Hazard Studies - Human
Controlled Experiments (EPA. 2019t) for details regarding these reviews.
Table 3-3 outlines the studies that evaluated neurobehavioral effects.14 Putz et al. (1979) exposed
12 adults (males and females) to 195 ppm methylene chloride (measured) or 70 ppm CO for four
hours; both exposures were designed to result in a COHb level of 5%. In a dual task, participants
manipulated a lever to position a beam in the center of an oscilloscope (to measure eye-hand
coordination) and also monitored peripheral stimuli visually for presence of an increase in light
intensity of signal (to measure visual peripheral changes). Methylene chloride resulted in a
decrease in visual peripheral performance of 7% at one and one-half hours and 17% at four hours
and a 36% decrease in eye-hand coordination at four hours only. CO resulted in a 23% decrease
in eye-hand coordination and an 11% decrease in visual performance at four hours. Both
chemicals resulted in similar auditory decrements (~ 16-20%). The authors conclude that the
tasks resulted in a decrease in speed and precision of psychomotor performance, which in turn, is
hypothesized to indicate a temporary decrease in CNS activation. They also note that effects
were observed usually only when the task was difficult or demanding (Putz et al.. 1979). The
study used a double-blind design but use of a single exposure concentration resulted in a medium
data quality rating.
Stewart et al. (1972) evaluated three adult males and reported increased peak to peak amplitude
visual evoked responses (VER) after a one-hour exposure to 514 ppm that returned to control
levels soon after exposure ceased. COHb levels increased in these subjects as well. These types
of VER changes have been observed to accompany initial phases of CNS depression (Stewart et
al.. 1972). Stewart et al. (1972) also reported symptoms of lightheadedness and difficulty
enunciating words. Although the more objective measures from this study such as VER are of
higher quality (with a medium data quality rating), EPA gave the symptom reports a low data
quality rating because it is not known whether subjects and investigators were blinded to the
subjects' exposure status.
13
The National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances (NAC/AEGL Committee)
develops AEGLs, which are applicable to emergency exposure periods ranging from 10 minutes to 8 hours. Three AEGLs are
established as air concentrations above which the general population (and susceptible subpopulations) could experience the
following:
	AEGL-1: notable discomfort, irritation, or asymptomatic, non-sensory effects that are not disabling and are transient
and reversible after exposure cessation;
	AEGL-2: irreversible or other serious, long-lasting adverse health effects or inability to escape; and
	AEGL-3: life-threatening health effects or death (Nac/Aegl. 2008b).
14	Several additional studies that linked methylene chloride exposure with COHb levels were also used in setting the
SMAC.
Page 247 of 753

-------
Winneke (1974) reported effects similar to Putz et al. (1979). Eight to 18 adult females were
exposed to 300, 500 or 800 ppm methylene chloride. Additional subjects were exposed to 50 or
100 ppm CO. At 800 ppm for four hours, methylene chloride resulted in decreases in all
psychomotor performance measures except one, and a majority of the measures (10 of 14) were
statistically significantly different from controls (p < 0.05 or < 0.01). Methylene chloride also
resulted in decrements in a visual task (flicker fusion performance) at > 300 ppm, with marked
depression at 800 ppm (p < 0.05 or < 0.01). Auditory tasks also showed changes (p < 0.05) in
several of the experiments, including at 300 ppm. However, visual and auditory effects were not
consistent; for example, another experiment within this publication did not result in effects at
300 or 500 ppm. The authors concluded that this impaired performance was a sign of CNS-
depression due to methylene chloride exposure. In contrast, no changes were observed after four
hours of CO exposure (Winme	). Overall, EPA gave this study a medium data quality
rating based on multiple exposure concentrations but use of a single blind method that was not
well described.
Another study (Gamberale et al. 1975) used an inhalation method with 14 males that included a
breathing valve that included menthol to disguise the odor of methylene chloride rather than a
chamber to generate methylene chloride concentrations in air. Gambeufe J M did not
identify significant decreases in tests of reaction time or a short-term memory test. These tests
used a repeated-measure design (exposure to 250, 500, 750 or 1000 ppm methylene chloride
consecutively for 30 minutes each, starting with the lowest exposure and successively moving to
the highest with no breaks in exposure). Each test was administered within each of the 30-minute
time periods. The subjects exhibited differences in perception of their own condition (p < 0.005);
the authors noted this to be a subjectively favorable change. Heart rate was slightly lower with
methylene chloride (not statistically significant). Other measures were not statistically
significantly different from controls except for one of the simple reaction time tests during one
exposure period. The authors provided very few details on the method of methylene chloride
generation, and they did not measure methylene chloride levels in the breathing valve in
inspiratory air. Thus, EPA gave the study a low data quality rating.
DiVincenzo et al. (1972.) evaluated cerebral and motor functions of males exposed to 100 or 200
ppm methylene chloride for two or four hours. The authors evaluated the time it took to insert
wooden pegs in a pegboard while simultaneously performing an arithmetic task. However, the
authors provided only a brief statement that no changes were observed in the pegboard exercise
or in subjective measures (also not defined). The authors did not report on results of the
arithmetic task. Based on lack of information regarding results as well as whether negative
controls were used, EPA gave this study a low data quality rating. Also, blinding was not
mentioned, further resulting in low confidence regarding any subjective measures.
Kozena et al. (1990) examined sixteen healthy male volunteers exposed to methylene chloride
for 1 hour using a double-blind experiment. Methylene chloride concentrations increased in
geometrical steps (five minutes each except for the last exposure, which was 10 minutes) from
zero to 720 ppm. The authors evaluated reactions to weak auditory stimuli and subjective
feelings (including sleepiness, fatigue, mood changes) before, during and after exposure and
found no differences from controls. Based on use of a half mask for exposure generation and
Page 248 of 753

-------
lack of understanding about comparability of the resulting exposure concentrations, EPA gave
this study a low data quality rating.
Winneke and Fodor (1976) exposed females to methylene chloride in an exposure chamber
conducted tasks that included adding numbers and letter cancelling (not further described),
which were then interrupted to determine performance on critical flicker frequency (CFF). The
authors report a methylene chloride-induced depression of CFF (p of 0.005). Winneke and Fodor
(1976) also apparently describe experiments by Winneke (1974) that are already described above
so those are not described here again. EPA gave this study a low data quality rating because
details were limited regarding the outcome assessment methodology and the lack of reporting the
results of the adding numbers component.
Other symptoms and effects have also been reported after acute methylene chloride exposures
from case reports. For example, Preisser et al. (2011) reported nausea and irritation. Effects on
lung, liver or kidney have also been reported in humans as primary signs of methylene chloride
toxicity (Nac/Aegl. 2008b). In some cases, high COHb levels (i.e., up to 40 percent) are also
observed (Nac/Aegl. 2008b).
Cardiotoxicity has been identified much less often or at higher concentrations. A few lethal cases
exhibited cardiotoxic effects. One fatality was attributed to myocardial infarction without any
signs of reported CNS depression, but other deaths due solely to cardiotoxic effects have not
been reported (Nac/Aegl. 2.008b). It is possible, however, that underlying heart disease may lead
to dysrhythmia and contribute to the cause of death from methylene chloride (Macisaac et al..
2013). Some non-lethal case reports in humans have identified electrocardiogram [ECG] changes
but at concentrations higher than those associated with CNS effects (I r \ 20 I t; \ I s.DR.
2000). Preisser et al. (2011) identified chest tightness (a possible cardiac sign). Increased COHb
concentrations, however, have been associated with decreased time to angina in persons with
cardiac disease while exercising (Nac/Aegl. 2008b). Based on this decreased time to angina,
EPA considers individuals with cardiac disease to be an important susceptible subpopulation as
further discussed in Sections and 4.4.5.
Animals
Neurological evaluations in animals during and after acute inhalation exposure to methylene
chloride have resulted in CNS depressant effects that include decreased motor activity, impaired
memory and changes in responses to sensory stimuli (	,011). Weinstein et al. (1972)
and Heppel and Neal (1944) reported decreased spontaneous activity in rodents after exposure to
5000 ppm for up to seven or 10 days, respectively. Clinical signs along with decreased activity
reported by Wein stein et al. (1972) suggested CNS depression. Kiellstrand et al. (1985) found
that mice exhibited an initial increase in activity, and then decreased activity, after acute
exposure > 600 to 2500 ppm. Rebert et al. (1989) identified visual and somatosensory responses
in an acute study at concentrations up to 15,000 ppm that collectively suggested CNS depressive
effects. Savolainen et a 0 identified increased preening by rats exposed to 500 ppm for six
days, and Dow (1988) found changes observed on an electroencephalogram (EEG) and effects
on somatosensory evoked responses after acute exposure by rats to > 2000 ppm methylene
chloride.
Page 249 of 753

-------
Shell Oil (19861 submitted under TSCA, evaluated liver changes in mice and rats at 2000 and
4000 ppm after 1 and 10 days. Mice exhibited changes in liver weights (decreased at one day,
increased at 10 days), but no changes in liver morphology. In contrast, all exposed rats had
increased numbers of eosinophils in centrilobular cells and seven of 10 rats at the highest
concentration exhibited increased incidence of mitotic figures in the midzone, adjacent to the
area with eosinophilia. The overall data quality rating for this study is high.
After short-term exposure, Bornschein et al. (1980). reported increased general activity and
delayed rates of habituation to a novel environment in rats exposed to 4500 ppm before (about 21
days) and/or during gestation (to day 17). Alexeeff and Kilgore (1983) identified a statistically
significant difference in a passive avoidance learning task among three-day old mice exposed to
-47,000 ppm methylene chloride via inhalation compared with controls. In contrast, these
authors did not observe any differences for 5- and 8-week old mice (Alexeeff and Kilgore.
1983).
Effects other than nervous system changes have also been reported in animals after acute
exposure. CD-I mice exhibited a localized immunosuppressive effect in the lung from inhalation
of 100 ppm methylene chloride for three hours (Aranyi et a 5). After exposure to 2000 and
4000 ppm after one or 10 days of exposure, mice exhibited changes in liver weights, whereas rats
exhibited increased numbers of eosinophils in centrilobular cells (both concentrations) and
increased incidence of mitotic figures (highest concentration) (Shell Oil. 1986). Mice exhibited
lung effects (on club cells) in this study at one day but not after 10 days (Shell Oil. 1986).
A few studies in animals have identified cardiac effects at higher concentrations.Clark and
Tinston (1982) as cited in (Nac/Aeel 2008b). first injected beagle dogs with adrenaline, exposed
them to methylene chloride for 5 minutes and finally challenged them with another adrenaline
injection. The ECso for cardiac sensitization to adrenaline was 25,000 ppm. Cardiac sensitization
occurred upon ventricular tachycardia/ventricular fibrillation. Two other studies cited by
NAC/AEGL (2008b) identified some additional cardiac effects but only after tracheal
cannulation and at concentrations of 15,00 ppm and higher (Aviado et 
-------
Known or possible association between death from accidents with nervous system effects have
been documented in an epidemiological study of methylene chloride and a supporting study on
solvents. Lanes et al. (1990) found methylene chloride exposure to be associated with excess
mortality from accidents at work (with 8-hr time-weighted averages (TWAs) ranging from below
detection to 1700 ppm). Furthermore, Benignus et al. (2011) modeled increases in fatal car
accidents from neurobehavioral changes resulting from small increases in solvent concentration.
Human fatalities have been documented in case studies where workers were using methylene
chloride, with estimated air concentration ranges and exposure durations that appear to overlap
with the human experimental studies that identified effects that were less severe. For example,
one person was found dead 20 to 30 minutes after being seen alive; air samples taken after
exposure were as low as 68-109 ppm at the level of the upper airways and 25,100 ppm at 25 cm
above the solvent surface (Nac/Aegt. 2008b). Also, individuals have been found dead after an
estimated 2 or 2.5 hrs of exposure with estimated air concentrations ranging from a 1-hr TWA in
a bathroom of 637-1060 ppm (with a 1-hr TWA in the bathtub of ~11,600 to 19,400 ppm) up to
53,000 ppm in a squash courtCNIOSH. 201 la; Nac/Aegl. 2008b). Information from these reports
is limited and imprecise because air concentrations are measured after the individual died or are
estimated based on amounts of methylene chloride used and room sizes and exposure durations
are also estimated and may not be well known.
Lethality data in animals does suggest a steep dose-response curve, with an increase in mortality
from 0 to 100% for an approximately twofold increase in exposure concentration (Nac/Aegl.
2008b). Appendix J presents additional details regarding fatalities associated with methylene
chloride exposure.
Government and non-governmental organizations have established emergency guideline
exposure levels for methylene chloride. The NIOSH guidance states that a value of 2300 ppm
(7981 mg/m3) as immediately dangerous to life or health (1DLH) (NIOSH. 1994). Individuals
should not be exposed to methylene chloride at this level for any length of time. The IDLH is
based on acute inhalation toxicity data in humans. The AEGL-3 values for death range from
12,000 ppm (42,000 mg/m3) to 2100 ppm (7400 mg/m3) for 10-min to 8-hr time periods,
respectively and are based on mortality from CNS effects in rats and COHb formation in humans
(Nac/Aegl. 2008b).
Given the possibility that death or other severe effects may occur within the range of
concentrations at which less severe effects occur, EPA considers Putz et al. (1979) to be the most
relevant study to estimate risks of effects from acute exposure.
Sections on liver effects (Section 3.2.3.1.2), nervous system effects (Section 3.2.3.1.4) and
immune system effects (Section 3.2.3.1.3) describe studies considered for modes of action for
these endpoints.
Page 251 of 753

-------
Table 3-3. Human Controlled Inhalation Experiments Measuring Effects on the Nervous System*
Suhji-ils
('iini'i-nlmliim
s
Duniliiiii
I'liulpiiiiiis (; nd liiiK-pninis)
iiu;isiiiv(I
COIII) \iilui-
IHll-l lS (ll)Sl-l'M-(l
kll'l'IVIHl'
Qli;ilil;iliM' d;il;i
(|ii:ilil\
i-\ :iln:il ion
6 males/6 females,
18-40 yrs,
nonsmokers,
good vision,
no prior solvent exposure
[subjects served as their
own controls],
Double blind design
(n=12)
0, 195 ppma
(measured)
4 lirs = three
80-min
blocks,
8-9 min rest
btwn blocks
1)	Dual task:
Eye-hand coordination/ visual
peripheral (4x, before/through
exposure, ending at 4 hrs)
2)	Auditory vigilance
(3x, early during and through
exposure period)
5.1% post-
exposure
After 4 hrs:
1)	36% j hand/eye; 17%j visual
peripheral (p < 0.01)
2)	-17%) b| auditory vigilance
(p<0.01)
After 1.5 hrs:
1) 7%) I visual peripheral (p < 0.01)
Putz et al.
(1979)
Medium; double-
blinded, single
concentration
11 males,
23-43 yrs,
nonsmokers
[pre-exposure values for
each subject served as
controls]
Experiment 2 e
(n=3):
986 ppm
(measured)
2 hrs
1)	Symptoms (1 hr pre-
exposure; throughout exposure)
2)	Visual evoked response
(VER) (lx before, 2x during
exposure and at 1 hr post-
exposure)
3)	Hematology/clinical
chemistry/urinary urobilinogen
(pre-exposure; up to 24 hrs post
exposure)
10.1% @
1 hr post-
exposure;
3.9% @ 17hrs
1)	Mild lightheadedness (2
subjects); difficult enunciation (1
subject)c
2)	VER - Alterations in all 3
subjects d



Experiment 3
(n=3):
mean = 691
ppm;
(514 ppm 1st hr;
868 ppm 2nd hr)
vapor
(measured)
2 hrs
1)	Symptoms (1 hr pre-
exposure; throughout exposure)
2)	VER (lx before, 2x during
exposure and ~ 1 hr post-
exposure)
3)	Hematology/clinical
chemistry/urinary urobilinogen
(pre-exposure; up to 24 hrs post
exposure)
8.5% @2.5
hrs post-
exposure b
^Lightheadedness (1 subject; 2nd
hr)
2)	VER - alterations (3 subjects)
3)	No changes
Stewart et al.
Medium for
VER; Low for
symptoms due to
lack of blinding

Experiment 4:
(n = 8):
515 ppm
1 hr
1)	Symptoms (1 hr pre-
exposure; throughout exposure)
2)	Hematology/clinical
chemistry {presumably pre-
exposure; up to 24 hrs post
exposure)
3.4% @
1 hr post-
exposure
1)	None identified
2)	No t in RBC (red blood cell)
destruction


Females
[unclear whether subjects
served as their own
controls],
Experiment 1
g,h
(n = 8):
0, 500 ppm
3.8 hrs
1)	Auditory vigilance (4x
during exposure)
2)	Visual critical flicker fusion
(CFF)

1)	Auditory: omission errors (p <
0.05)
2)	Visual CFF: Not stat. sig
(ANOVA1 for both)
Winneke,
(1.974)
Medium; single
blinded
Page 252 of 753

-------
Suhji-ils
('iini'i-nlmliim
s
Duniliiiii
I'liulpiiiiiis (; nd liiiH-pniiiis)
I1H';|SIIIV(I
COIII) \iilui-
IHll-l lS (ll)Sl-l'M-(l
kll'l'IVIHl'
Qll;ilil;iliM' d;il;i
(|ll;ilil\
i-\ ;iln;ilion
authors conclude that the
study was single-blinded
based on lack of odor
(expect at 800 ppm)
Experiment 2
(n = 6):
0, 300, 800
ppm
3.8 hrs
1)	Auditory vigilance (4x
during exposure)
2)	Visual CFF (lx before; 4x
during exposure)

1)	Auditory: omission errors (p <
0.05)
2)	Visual CFF (p < 0.05) (ANOVA
for both)



Experiment 3
(n = 6):
0, 300, 500
ppm
3.8 hrs
1)	Auditory vigilance (4x
during exposure)
2)	Visual CFF (lx before; 4x
during exposure)

1)	Auditory: not stat. sig.
2)	Visual CFF: not stat. sig.
(ANOVA for both)



Experiment 2 +
3
(n = 12):
0, 300 ppm
3.8 hrs
1)	Auditory vigilance (4x
during exposure)
2)	Visual CFF (lx before; 4x
during exposure)

1)	Auditory: omission errors (p <
0.05)
2)	Visual CFF (p< 0.01)
(ANOVA for both)



Experiment 4 a
(n = 18):
0, 800 ppm
4 hrs
1)	Auditory vigilance (2x
during exposure)
2)	Visual CFF (lx before; 3x
during exposure)
2) Comprehensive battery of 14
psychomotor tests f (near end of
exposure)

1)	Auditory: reaction time
(p < 0.05; ANOVA)
2)	Visual CFF: not stat. sig.
3)	10 tests I (5 (3) p < 0.01; 5 (3) p <
0.05); Steadiness (1 test),
Eland precision (2 right hand tests),
pursuit tracking (single test) not stat.
sig. (paired t-values)


Males,
20-30 yrs, identified as
healthy
(n = 14)
0, 250, 500,
750, 1000 ppm
2 hrs
(30 min each
to increasing
concentration
without a
break in
exposure)
1)	Subjective perceptions
2)	Reaction time (RT) -
addition
3)	Simple reaction test 1
4)	Short-term memory
5)	Simple reaction test
(Each test conducted during
each exposure concentration
and for controls)
-5%
1) Perceptions - individual measures
not statistically significant; as a
whole, changes were observed (p <
0.005), although authors described
this as subjectively positive
3) Simple RT 1 - changes only at the
highest concentration (p < 0.05)
2, 4 and 5) RT addition, Short-term
memory, simple RT 2 - no stat. sig.
changes
Gamberale et
al. (1975)
Low - use of
breathing valve
with limited
details and no
analytical
monitoring;
Impact of using
menthol not
known
Males, 28 to 60 yrs,
inclusion required medical
approval
100, 200 ppm
(n= 11)
2 and 4 hrs
1)	Pegboard activity - time
required to place pegs in proper
holes (for 2 hr: at beginning, 1
hr and lhr/40 min; for 4 hr:
added time at 2 and 3 hrs; 5
trials at each timepoint),
2)	Subjective measures
(continuous surveillance)

1)	No changes (details not provided)
2)	No changes (details not provided)
DiVincenzo
et al. (1972)
Low - lack of
detail regarding
results and use of
controls
Page 253 of 753

-------
Suhji-ils
('iini'i-nlmliim
s
Duniliiiii
I'liulpiiiiiis (; nd liiiH-pniiiis)
I1H';|SIIIV(I
COIII) \iilui-
IHll-l lS (ll)Sl-l'M-(l
kll'l'IVIHl'
Oll:ilil;i 1 i\ d;il;i
(|ll:ilil\
i'\ ;illl;ilion
Males, 19-21 yrs, healthy,
paid volunteers,
double-blind design
0 (n = 42)
Increasing cone
to approximate
144 ppm
(w/peak of 720
ppm at end of
exposure)
(n = 16)
1 hr
1)	weak auditory stimuli (5 to
25 sec during 1 hr, repeated 3x
- before, during and after
exposure)
2)	Subjective measures
(sleepiness, fatigue, changes in
mood)
NA
1)	No changes
2)	No changes
Kozena et al.
(1.990)
Low - lack of
information on
exposures
Females, 22-31 yrs,
single-blind design not
well described
[subjects served as their
own controls]
0, 500 ppm
(n = 12, groups
of 3)
2 hrs 20 min
1)	alternating task of adding
numbers and letter cancelling
2)	Visual CFF (4 x during
exposure)
NA
1)	No changes
2)	Visual CFF (p of 0.005)
Winneke and
Fodor (1.976)
Low - limited
details on
outcome method
and results
"Hematology measured in one study
a CO also evaluated but not included in table
b Estimated from graph
c Individuals were inadvertently exposed to methylene chloride before exposure, resulting in breath levels of 10 ppm and higher (graph is exponential and difficult to read above 10); this
didn't appreciably alter COHb levels.
d Information on statistical significance not presented.
e Experiment 1 measured COHb in one individual after 213 ppm vapor exposure for 1 hour; a value of 2.4% @ 3 hrs post-exposure was observed
f Tapping (hand movements without eye-hand coordination- 1 test); two plate tapping (arm movements: some eye-hand coordination - 1 test); steadiness (hand/arm - 2 tests); hand precision
(6 total tests - 3 for each hand); pursuit tracking (visual-motor control of large muscle groups - 1 test); reaction speed (visual/gross motor reaction - 3 tests)
B There was an experiment 0 (pilot study) - 0, 500 ppm (n = 12) - results of visual CFF show a decrement (p < 0.01); auditory vigilance and other un-named tasks were not s.s.
h The authors state that the measured values are 317 ppm, 470 ppm and 751 ppm; those values are not included in the table because it is not clear whether they represent averages across
experiments or are specific to one of the experiments.
1ANOVA = analysis of variance
Page 254 of 753

-------
3.2.3.1.2 Liver Effects
A limited number of human studies and multiple animal studies have identified liver effects associated
with methylene chloride exposure. EPA focused on evaluating human epidemiological studies as well as
chronic inhalation studies in animals. Other animal studies discussed in previous peer-reviewed
assessments are considered acceptable for supporting the weight of scientific evidence.
Humans
Few epidemiological studies evaluated non-cancer liver effects, and limited evidence was identified in
studies that measured relevant endpoints. Three acceptable epidemiological studies measured bilirubin
and serum enzyme concentrations in workers exposed to methylene chloride (Soden. 1993; General
Electric Co. 1990; Ott et at.. 1983b).15 Two of these studies found some evidence of increasing levels of
serum bilirubin with increasing exposure but no consistent trends for other serum hepatic enzyme levels
(y-glutamyl transferase, aspartate amino transferase (AST) and alanine transaminase (ALT)) (General
Electric Co. 1990; Ott et at.. 1983b). EPA gave medium data quality ratings to all three studies.
Although increased bilirubin is of concern, EPA did not consider this to be an endpoint appropriate for
considering in the current risk evaluation because these data don't provide clear evidence of adverse
liver effects.
In the updated literature search, EPA identified only one additional study that evaluated any liver
effects. Silver et al. (2014) reported no increase in standardized mortality ratios (SMR) for cirrhosis and
other chronic liver diseases in a cohort of microelectronics and business machine workers exposed to
multiple solvents, metals, glycol ethers and other chemicals. Individuals were exposed for an average of
5.2 to 9.8 yrs. depending on sex and whether they were salaried or hourly from 1969 to 2001 when
compared with death rates in the U.S. population. There was some exposure to methylene chloride, but
the SMRs were not specific for methylene chloride exposure. Silver et al. (2014) received a medium
data quality rating.
Overall, the human data are not conclusive with respect to methylene chloride's association with liver
effects based on the limited database and endpoints evaluated.
Animals
Section 3.2.3.1.2 outlines liver effects in chronic and subchronic studies. Section 2.2.3.1.1 describes
shorter-term and acute exposure studies. In chronic inhalation studies in animals, liver effects were often
the most sensitive effects. Rats exhibited vacuolization and sometimes necrosis (Nitschke et at.. 1988a;
NTP. 1986; Burek et al.. 1984). hemosiderosis (NTP. 1986) and acidophilic and basophilic foci (Also et
at.. 2014a). Mice showed degenerative changes in hepatocytes in one chronic inhalation study (NTP.
1986). No liver effects were observed in hamsters after chronic inhalation (Burek et al.. 1984). U.S. EPA
(2011) notes that vacuolization was consistently identified, and lipids were observed in the vacuoles.
Data quality ratings for the chronic studies are high.
In the updated literature search, Aiso et al. (2014a). a chronic inhalation study, found that relative liver
weights of rats were decreased > 10% only at the lowest concentration (1000 ppm) in males (p < 0.01).
In females, absolute and relative liver weights were increased by 11%, 25% and 25% and by 11%, 22%
and 29% at 1000, 2000 and 4000 ppm, respectively (p < 0.01). In males, acidophilic and basophilic cell
foci were increased at 1000 or 2000 ppm without a dose response. In females, lesions were increased
15 GE (1990) is the same reference as
(1990). which is cited in U.S. EPA (20.1.1).
Page 255 of 753

-------
and showed more of a dose-response, although Aiso et al. (2014a) did not report results of trend tests.
The authors classified the altered acidophilic and basophilic cell foci as preneoplastic proliferative
lesions. However, EPA did not observe correlations between the pre-neoplastic foci and tumors in this
study. For example, these foci were not significantly increased in mice, even though the incidences of
hepatocellular adenomas and carcinomas were significantly increased in a dose-response trend. Also,
these foci were also not well correlated in rats. Therefore, EPA considers the foci identified in this study
to be non-neoplastic and rats appear to be more sensitive to the effect.
In subchronic inhalation studies, rats and dogs exhibited fatty livers, mice exhibited hepatic
degeneration and vacuolization and monkeys exhibited borderline effects (NTP. 1986; Haun et al... 1972;
Haun et al.. 1971). However, a 90-day study by Leuschner	0 found no changes in liver
weights, related biochemistry or histopathology in Sprague-Dawley rats or Beagle dogs at
concentrations as high or higher than other studies that showed effects. The reason for this negative
study is not clear but Leuschner et al. (1984) did not identify the organs evaluated histologically and
identified results of biochemical and other analyses in the text only as "no intolerance phenomena"
without any tabular information presented. EPA identified a 90-day oral dog study submitted under
TSCA that was not reported in U.S. EPA (2011). Four dogs at the highest dose of 200 mg/kg-bw/day
exhibited inflammatory cell foci in livers compared with one control animal with the effect (General
Electric Co. 1976b). Foci were slight or very slight in severity and not accompanied by biochemical
changes. This study received a high overall data quality rating.
Mechanistic Data
Although U.S. EPA (2011) discussed modes of action related to liver tumors, limited research has
focused on the mechanisms related to non-cancer liver effects. When U.S. EPA ( ) investigated
metrics for dose-response modeling, considering the metabolites of the CYP pathway showed more
consistency between the inhalation and oral routes compared with results of the GST pathway or
considering AUC of the parent compound. Although not definitive, this could suggest metabolites of the
CYP pathway may be involved in non-cancer liver endpoints. U.S. EPA ( ) indicated exposure of
Wistar rats to 500 ppm resulted in increased hemochrome content in liver microsomal cytochrome P450
(CYP) (Savolainen et a 7), which could represent an adaptive response. Also, mouse hepatocyte
degeneration was related to dissociated polyribosomes and rough endoplasmic reticulum swelling
(Weinstein et al.. 1972).
In the updated literature search, EPA identified a few studies that examined changes in gene and protein
expression and enzymatic activities in livers of rats or in one case, fish. Oral studies in rats and one
study in fish identified liver-related biochemical changes but none provide definitive or specific
information on modes of action for methylene chloride related to non-cancer liver toxicity. In rats,
methylene chloride was associated with increased biliary output after induction of nitric oxide (NO) by
carbon monoxide (CO), which increased biliary excretion of glutathione (GSH) (Chen et al.. 2013). Kim
et al. (2010) found expression of the protein a-2 |i globulin was decreased (0.92 vs. 1), whereas GST-a
(1.13 vs. 1) and phenylalanine hydroxylase (1.17 vs. 1) were increased in livers of rats orally exposed to
methylene chloride. Likewise, seven of 1,100 proteins (three paralogues of GST, P-l-globin - part of
hemoglobin that binds C02, two hemoglobin P-2 subunits and a-2 globulin) in livers of rats dosed orally
with methylene chloride were downregulated compared with controls (Park and Lee. 2014). In rat livers,
methylene chloride also downregulated genes that are downregulated in T-cell prolymphocytic leukemia
(Kim et al..: ) Dzul-Caamal et al. (2013) didn't identify increased formaldehyde or reactive oxygen
species (ROS) as H2O2 in livers of fish but identified increasing lipid peroxidation and oxidation of
proteins with increasing doses of methylene chloride.
Page 256 of 753

-------
Table 3-4. Liver Effects Identified in Chronic and Subchronic Animal Toxicity Studies of Methylene C
lloride
T.irgcl
Orjiiin/
S\s(cm
Sluclj
Tj pc
Species/
S(r;iin/Sc\
(Nil in hoi'/
lil'Olip)
I'Aposlll'C
Roulc
Doses/
Concenlr;ilions
Dui'iilion
\o\i:i./
i.o\i:i.
reported
In si ii (It
iiulhors
\o\i:i./
i.o\i:i.
(111^/1111 or
m/k-
d;i\) (Se\)
I'.ITecl
Reference
Diilii
Qu;ilil\
l-'.\ iiliiiiiion
Hepatic
Chronic
Rat, F344, M/F
(n=100/group)
Inhalation
, vapor,
whole
body
0,3510, 7019 or
14,038 mg/m3 (0,
1000, 2000 or
4000 ppm)
6
hours/day,
5
days/week
for 2 years
NA
LOAEL=
3510
(M/F)
Hepatocyte
vacuolation and
necrosis,
hemosiderosis
in liver (M/F);
hepatocyte-
megaly (F)
NTP (1986)
High
Hepatic
Chronic
Rat, Sprague-
Dawley, M/F
(n~190/group)
Inhalation
, vapor,
whole
body
0, 1755, 5264 or
12,283 mg/m3 (0,
500, 1500 or
3500 ppm)
6
hours/day,
5
days/week
for 2 years
NA
LOAEL=
1755
(M/F)
Hepatocyte
vacuolation
(M/F);
multinucleated
hepatocytes (F)
Burek ef al.
(1984)
High
Hepatic
Chronic
Rat, Sprague
Dawley, M/F
(n=180/group)
Inhalation
, vapor,
whole
body
0, 176, 702 or
1755 mg/m3 (0,
50, 200 or 500
ppm)
6
hours/day,
5
days/week
for 2 years
NA
NOAEL=
702
(F)
Hepatic lipid
vacuolation and
multinucleated
hepatocytes
Nitschke et
al. (1988a)
High
Hepatic
Chronic
Mouse,
B6C3F1, M/F
(n=100/group)
Inhalation
, vapor,
whole
body
0, 7019 or
14,038 mg/m3 (0,
2000 or 4000
ppm)
6
hours/day,
5
days/week
for 2 years
NA
LOAEL =
7019
(F)
Hepatocyte
degeneration; (f
hepatocellular
adenoma or
carcinoma)
NTP (1986)
High
Hepatic
Chronic
Mouse,
B6C3F1, M/F
(n=20/group)
Inhalation
, vapor,
whole
body
0, 1843, 3685,
7371, 14,742 or
29,483 mg/m3
(0, 525, 1050,
2100, 4200 or
8400 ppm)
6
hours/day,
5
days/week
for 13
weeks
NA
NOAEL=
7371
(F);
NOAEL =
14,742
(M)
Hepatocyte
centrilobular
degeneration
NTP (1986)
High
Page 257 of 753

-------
Tiiriiel
Origin/
S\s(em
Sluclj
1 J |H'
Species/
S(r;iin/Sc\
(Number/
jiroup)
l-lxposurc
Roulc
Doses/
('onccnlmlions
l)ur;ilion
NOAII./
1.OA l-'.l.
reported
In s(ii(l\
iiulhors
NOAII./
1.OA l-'.l.
(niii/iii-4 or
niii/kii-
(l;i\) (Sex)
KITecl
Kelerenee
Diilii
Qu;ilil>
l'l\;iliiiilion
1 lepalic
Chronic
kal, 1-44, \l I-"
(n=170/group +
270 controls)
()ral,
drinking
water
ii, (i, 52, 125 or
235 mg/kg-day
(M);
0, 6,58, 136 or
263 mg/kg-day
(F)
1 <>4 weeks
\ \
\o\i:i.
6
(M/F)
' Non-
neoplastic
Foci/areas of
alteration
(M/F); t
incidence of
neoplastic
nodules; fatty
liver changes
(incidence N/A)
Sci'oia el al
(1986a)
iiigi.
Hepatic
Subchron
ic
Rat, F344, M/F
(n=30/group)
Oral,
drinking
water
0, 166, 420 or
1200 mg/kg-day
(M);
0, 209, 607 or
1469 mg/kg-day
(F)
90 days
NA
LOAEL=
166 (M);
LOAEL =
209 (F)
Hepatic
vacuolation
(generalized,
centrilobular, or
periportal)
Kirschman et
al. (1986)
Low
Hepatic
Chronic
Mouse,
B6C3F1, M/F
(n=125, 200,
100, 100 and
125 [M];
n=100, 100, 50,
50 and 50 [F])
Oral,
drinking
water
0, 61, 124, 177
or 234 mg/kg-
day (M);
0, 59, 118, 172
or 238 mg/kg-
day (F)
104 weeks
NA
NOAEL=
185
(M/F)
Some evidence
of fatty liver;
marginal
increase in the
Oil Red-O-
positive
material in the
liver
Hazleton
Labs (1983)
Medium
Hepatic
Subchron
ic
Mouse,
B6C3F1, M/F
(n=30/group)
Oral,
drinking
water
0, 226, 587 or
1911 mg/kg-day
(M);
0, 231,586 or
2030 mg/kg-day
(F)
90 days
NA
NOAEL=
226 (M)
Hepatic
vacuolation
(increased
severity of
centrilobular
fatty change)
Kirschman et
Low
Hepatic
Chronic
Rat.
F344/DuCrj
Inhalation
. vapor,
whole
body
0.3510. 7019 or
14.038 nig/m' (0.
1000. 2000 or
4000 ppm)
6
hours/day.
5
days/week
for 2 years
NA
LOAEL =
3510
mg/nv' (F)
Increased
basophilic foci
and increased
abs/rcl liver wl
(p<0.01)
Aiso et al.
(2014a)
High
Page 258 of 753

-------
Tiiriiel
Origin/
Sjsiom
Sliid>
1 J |H'
Species/
S(r;iin/Sc\
(N u in her/
Jil'Olip)
l-lxposurc
Uoule
Doses/
('onccnlr;ilions
l)ur;ilion
NOAM./
1.OA l-'.l.
reported
In s(ii(l\
iiulhors
NOAII./
1.OA l-'.l.
(nig/nr* or
in vi/lvli-
(l;i>) (Sex)
r.iToci
Hcld'cnce
Diilii
Qu:ilil>
ll\iiliiiilioii
Hcpnlic
Subchron
ic
Dog/Beagle
(M/F)
(4/scx/ group)
Oral
0. 12.5. 50. 200
mg/kg-bw/day
90 days
Not
Reported
NOAF.I. =
200
mg/kg-
bw/day
No changes in
clinical
chemistry, gross
pathology,
organ weight, or
histopathologica
1 lesions
General
Electric Co
f1976b)
High
Page 259 of 753

-------
3.2.3.1.3 Immune System Effects
EPA identified a limited number of human, animal and mechanistic studies of immune system
effects. Some studies identified effects associated with methylene chloride but results are limited
and conflicting.
Humans
From the updated literature search, EPA identified one epidemiological study that addressed an
immune-related endpoint. Chaigne et al. (2015) is a case control study evaluating Sjogren's
syndrome, which is an autoimmune epithelitis characterized by dry eyes and mouth, physical
weakness and joint pain. Systemic symptoms are possible and individuals with this syndrome
have an increased risk of lymphoma. The study identified 175 cases at three university hospitals
in France and used a comparison group of healthy individuals from the same hospitals. The
authors assessed exposure using a published job exposure matrix that accounted for probability,
intensity, frequency and duration of exposure. The study authors did not adjust for confounding
but did match cases and controls for age and gender. Cases and controls had similar smoking
rates and socio-economic and socio-professional levels.
Exposure to methylene chloride was associated with Sjogren's syndrome based on an odds ratio
(OR) of 9.28 (95% confidence interval (CI): 2.60-33.0) (p< 0.0001) (13 cases vs. 3 controls).
Among patients with anti-SSA or anti-SSB antibodies16, the OR was 11.1 (95% CI: 2.38-51.8) (p
< 0.001). For these two measures, methylene chloride had the highest ORs compared with other
compounds. High cumulative exposure (exposure score > 1) to methylene chloride was not
statistically significantly associated with Sjogren's syndrome, although the association was still
greater than 1.0 (OR: 3.04; 95% CI: 0.50 - 18.3) (Chaigne et al.. 2015). EPA determined an
overall data quality rating of medium for Chaigne et al. (2015) due to lack of information on
recruitment, participation and exposures.
Among U.S. Air Force base workers, men exhibited an increased risk of bronchitis-related
mortality when exposed to methylene chloride (hazard ratio (HR): 9.21; 95% CI: 1.03-82.69)
(Radican et al.. 2008). The HR is based on a total of four exposed cases and comparison of exposed
and unexposed male workers. There could be multiple causes of the bronchitis (e.g., infection or
other inflammatory processes). The authors used employment for at least one year as the exposure
criteria, and exposure levels were not estimated but methylene chloride use was linked to specific
departments at the air base (Radican et al.. 2008). The model adjusted for age, race and gender,
and evaluated 5-calendar year ranges but didn't adjust for socioeconomic status, which was quite
different between exposed and control workers (i.e., salaried workers were < 1% and 61%
among cases and controls, respectively). The study also did not adjust for co-exposures, even
though 21 additional solvents and chemicals were evaluated separately. The study received a
medium data quality rating. Lack of information on cause of bronchitis, exposure, the limited
16 SSA and SSB refer to Ro and La, respectively. These are ribonucleoprotein complexes (not compounds foreign to
the body) and anti-SSA and anti-SSB are antibodies mounted in response to these complexes (Moutsopoulos and
Zerva. 1990).
Page 260 of 753

-------
numbers of cases and the lack of adjustment for other chemical co-exposures makes it difficult to
make strong conclusions regarding the association between methylene chloride and bronchitis.
hoechst celanese cc	evaluated deaths from multiple causes in workers at a CTA fiber
production work site in Maryland, as identified on death certificates, for workers employed from
1970 to 1989. Slight elevations in risk of mortality due to influenza and pneumonia were
observed (SMR - males: 1.25; females: 4.36) when comparing workers ever exposed to the
highest exposure group (> 350 ppm - ~ 700 ppm) to the Maryland county population in which
the plant was located. The authors reported no statistically significant excesses of deaths but did
not report the 95th % confidence intervals for the SMR. Workers in this highest group could have
had portions of their work history exposed to lower (or no) concentrations. Employees may have
also been exposed to ethers, halogenated hydrocarbons, hydrazines, inorganic dusts and many
other compounds). EPA gave this study a data quality rating of medium. Because the comparison
group included the working and non-working population, any effects of methylene chloride may
have been attenuated based on greater illness in the controls unrelated to methylene chloride
exposure, and some effects might have been associated with other chemical exposures that were
not accounted for in the models. For these reasons, firm conclusions regarding the association
with methylene chloride cannot be made from this study.
Hearne and Pifer (1999). in Part I of their study, found significantly lower than expected
numbers of deaths due to infectious and parasitic diseases among triacetate film production
workers compared with death rates/causes of individuals in the general population in New York
(excluding New York City) in a 1946-70 cohort (employed in multiple divisions) followed
through 1994 (SMR = 0; 95% CI: 0-66; p^0.05). Although the study did not control for other
chemical exposures, the analysis was limited to employees hired after methylene chloride
became the principal solvent. (The authors do note that a 80% methylene chloride/20%) methanol
mixture was used in one of the divisions.) Employees worked for at least one year in one or more
of the divisions. Exposure was calculated by multiplying methylene chloride air concentrations
by the number of years exposure. For all diseases of the respiratory system, the SMR was 90
(95%o CI: 58-134)17 (also compared with the New York state population). Similar to the previous
study (hoechst celanese corp. 1992). the comparison populations of Hearne and Pifer (1999)
included working and non-working individuals and thus could include individuals who may be
not working due to illness.
Hearne and Pifer (1999) also conducted an analysis of employees in the roll coating department
(Part II); about 30% were hired before methylene chloride was introduced. Similar to Part I,
workers were employed for at least 1 year. The SMR for infectious and parasitic diseases was 67
(95%o CI: 14-197)18 using unexposed Kodak Rochester employees as the comparison. The
study's strength included its use of air monitoring values (> 1500 area samples and > 2500
personal monitoring samples for the Part I analysis). This study was rated high for data quality.
The authors note that for Part I, regression modeling was adjusted for age, calendar year and time
from first exposure, but it is not clear whether this was also done for the Part II analysis.
17	Using a similar metric as other studies, the SMR would be 0.90 (95% CI: 0.58-1.34).
18	Using a similar metric as other studies, the SMR would be 0.67 (95% CI: 0.14-1.97).
Page 261 of 753

-------
Lanes et al. (1993) assessed mortality among employees at a CTA fiber manufacturing plant in
Rock Hill, South Carolina. Workers were employed for at least three months in jobs that entailed
exposure to the highest concentrations of methylene chloride (median exposures of 140 to 745
ppm as 8-hr time-weighted averages). Methanol and acetone were also present but Lanes et al.
(1993) didn't control specifically for these compounds. The analysis did control for age, race,
gender and calendar period. The authors did not identify an increased risk of death from
nonmalignant respiratory disease (SMR = 0.97; 95% CI: 0.42-1.90). The comparison death rates
were taken from York County, South Carolina and could mask effects from methylene chloride
if the illness rates unrelated to methylene chloride differed between workers and the county
population. This study received a data quality rating of medium.
Animals
EPA identified no new animal studies that addressed immunomodulation in the updated literature
search. U.S. EPA (2011) summarized two animal toxicity studies. Aranyi et al. (1986) evaluated
several measures of immune response in acute inhalation studies using female CD-I mice. Mice
were challenged with live aerosolized Streptococcus zooepidemicus while simultaneously being
exposed to methylene chloride vapor or filtered air. The authors recorded deaths over a 14-day
period. Similarly, the authors measured clearance of aerosolized Klebsiella pneumoniae by
pulmonary macrophages from CD-I mouse lungs 3 hours after infection, comparing methylene
chloride to air exposures. After a single 3-hour exposure to 95 ppm methylene chloride, deaths
were increased by 12.2% (p < 0.01) from S. zooepidemicus infection compared with controls.
Bactericidal activity of macrophages against K. pneumoniae was decreased by 12% (p < 0.001).
In contrast, no changes in mortality rates or bactericidal activity were observed with either single
or five daily 3-hr exposures to 51-52 ppm. EPA evaluated this study, which received a data
quality rating of medium.
Warbrick et al. (2003) exposed Sprague-Dawley rats to 0 or 5 187 ppm methylene chloride for 6
hrs/day, 5 days/week for 28 days. On day 23, all rats were injected with sheep red blood cells.
Immunoglobulin M (IgM) antibody responses did not differ between methylene chloride-
exposed rats and negative controls. Relative spleen weights were reduced in females. This study
received a data quality rating of high.
NTP (1986) identified splenic fibrosis at > 2000 ppm in rats and splenic follicular atrophy in
mice at 4000 ppm in a two-year inhalation study. Other two-year inhalation studies (Nitschke et
al.. 1988a; Burek et al.. 1984) did not identify histopathological changes in the spleen, lymph
node or thymus of rats or hamsters. None of the two-year studies evaluated functional immunity
or identified patterns of inflammatory cells in the respiratory tract. None of these studies found
increased infections in dosed animals. All two-year studies received high data quality ratings.
Mechanistic Data
U.S. EPA (2011) did not discuss any mechanistic//'// vitro studies related to immunotoxicity. EPA
identified only two relevant studies from the updated literature search that address immune-
related activity. In one study, Kubulus et al. (2008) treated male rats with hem in arginate,
induced hemorrhage, then treated the rats with a heme oxygenase-1 blocker, and finally
Page 262 of 753

-------
administered methylene chloride. Methylene chloride treatment resulted in decreased pro-
inflammatory cytokine TNF-alpha and increased the anti-inflammatory cytokine IL-10 levels,
similar to treatment with hemin arginate alone. The authors hypothesized that the MOA for these
changes in cytokine levels was related to carbon monoxide generation (Kubulus et at. 2008).
Mitochondrial activity was assessed by measuring cell viability of peripheral blood mononuclear
cells (PBMC) of carp (Cyprinus carpio carpio), and ROS were also evaluated in PBMC by
measuring oxidation of substrates that generate fluorescent compounds (Uraga-Tovar et at..
2014). Methylene chloride increased mitochondrial activity and H2O2 in a dose-dependent
fashion. Overall, the authors demonstrated immunomodulary effects of methylene chloride in
PBMC of carp (Cyprinus carpio carpio) that included an acute pro-inflammatory state. Reports
of measuring ROS have not been performed on PBMC of the carp prior to publication by Uraga-
Tovar et al. (2014). Therefore, conclusions from the study should be considered with caution and
cannot be compared with other compounds.
3.2.3.1.4 Nervous System Effects
Nervous system effects related to methylene chloride exposure include effects related to CNS
depression in humans as well as spontaneous activity and other effects in animals.
Developmental neurotoxicity has also been observed in human studies and a limited number of
animal studies. A limited number of mechanistic studies are also available. EPA focused on
evaluating the human experimental studies. Previous peer-reviewed assessments discussed the
animal and in vitro studies, and these are considered acceptable for supporting the weight of
scientific evidence. This section focuses on both longer-term and developmental neurotoxicity
studies; section 3.2.3.1.1 describes other acute studies.
Nervous System Effects in Adults
Humans
Silver et al. (2014) reported no increased deaths from malignancies (SMR of 0.07 with 95% CI
of 0.0 to 3.83) or nonmalignant diseases of the nervous system from methylene chloride
exposure (SMR 1.04 with 95% CI of 0.83 to 1.31) in a cohort of microelectronics and business
machine workers exposed at least 91 days from 1969 to 2001 when compared with death rates in
the U.S. population (control group). The characteristics of the general population are likely to
differ from the worker population; often, morbidity and mortality rates are lower for workers
than for the full population, which includes individuals who are unable to work due to illness (Li
and Sung. 1999). Using this dissimilar control group could mask possible effects observed in
workers. Also, the model didn't adjust for other chemical exposures. This study received a data
quality rating of medium.
In a case-control study of occupational exposure in a plastic polymer plant that received a data
quality rating of medium, exposure to methylene chloride was associated with neurological
symptoms (i.e., dizziness and vertigo) (General Electric Co. 1990). The high methylene chloride
exposure group was exposed to a mean concentration of 49 ppm. It is likely that workers were
exposed to other chemicals in addition to methylene chloride (e.g., phenol and small amounts of
other chemicals).
Page 263 of 753

-------
In a study designed to evaluate persistence of nervous system effects, Lash et al. (1991)
examined retired aircraft maintenance workers employed in jobs associated with paint stripping,
which mainly use methylene chloride. Workers were exposed for > 6 years with an average
length of retirement of approximately five years. Controls were retired mechanics at the same
maintenance base where aircraft are maintained/repainted and that had little solvent exposure.
The study evaluated 33 symptoms primarily related to CNS effects and physiological
measurements. The only large differences between the exposed and control groups was a lower
score on attention tasks (effect size approximately -0.55, p = 0.08) and complex reaction time
(effect size approximately -0.40, p = 0.18) and a higher score on verbal memory tasks (effect
size approximately 0.45, p = 0.11). Sample sizes are low, and the study does not discuss other
possible pollutant exposures (Lash et al.. 1991). EPA gave this study an overall data quality
rating of medium.19
Data from several cohorts report SMRs related to suicide risk. Hearne and Pifer (1999) report
SMRs of 1.8 in two separate cohorts of workers in triacetate film production in Rochester, New
York (95% CI: 0.98-3.0 for one cohort and 0.81-3.4 for the other cohort). Similarly, hoechst
celanese cor	reports increased risk for the highest exposure group of 350-700 ppm in
Maryland triacetate fiber production workers (SMR = 1.8; 95% CI: 0.78- 3.6). Tomenson et al.
(2011) didn't identify increased risk. Data quality ratings are high for Hearne and Pifer (1999)
and medium for hoechst celanese corp (1992) and Tomenson et al. (2011). Lanes et al. (1993)
identified an SMR of 1.19 for suicide risk but U.S. EPA (2011) states that the SMR appears to be
incorrect and should be 0.77 (based on numbers of reported expected and observed cases).
Animals
A subchronic study identified CNS depressive effects (incoordination, lethargy) in dogs,
monkeys and mice, but not rats; brain edema was also observed in dogs (Haun et al.. 1971).
Thomas et al. (1972) identified increased activity in mice after 14 weeks exposure to 25 ppm but
no effects at 100 ppm. In contrast, a 13-week study using concentrations up to 2000 ppm did not
identify any changes in sensory stimuli responses (Mattssom et al.. 1990) but the measurements
were conducted at least 65 hrs after the last exposure and thus, the study could only assess
persistence of effects, not reversible effects that occurred during exposure.
Developmental Neurotoxicity
Humans
Between 2006 and 2015, five studies (Talbott et al. (2015): Roberts et al. (2013): Kalkbrenner
(2.010): Windham et al. (2006): von Ehrenstein et al. (2.014).); see Tables 4, 38, 41, and 57 in
supplemental file Data Extraction Tables for Human Health Hazard Studies) investigated the
19In an evaluation of acetate film workers with similar results to other studies. Cherry et al. (1983) found exposure to
methylene chloride was statistically significantly associated with sleepiness and tiredness during the morning shift,
as well as changes in mood and a deterioration in digit symbol substitution tests. However, due to a loss of more
than 50% of the participants with no comparison in attributes with individuals studied. Cherry et al. (1983) was
given an unacceptable rating and cannot be relied upon to make conclusions.
Page 264 of 753

-------
association between modeled air emissions or outdoor air concentrations of numerous chemicals
(including the 33-37 HAPs, or even more pollutants) and autism spectrum disorder (ASD) in
regions across the United States. Methylene chloride was among the few chemicals in these
studies that consistently identified odds ratios greater than one (ranging from 1.08 to 1.9),
although most of the results lacked statistical signifacnce with the lower end of the confidence
interval ranges including values less than 1.0.
Animals
Bornschein et al. (1980) found delayed rates of behavioral habituation to novel environments in
offspring from female rats exposed to 4500 ppm methylene chloride via inhalation before and/or
during gestation. The effects were observed as early as 10 days of age in both sexes and still
observed in 150-day male (but not female) rats. Alexeeff and Kilgore (1983) identified a
statistically significant difference in a passive avoidance learning task among three-day old mice
exposed to -47,000 ppm methylene chloride via inhalation compared with controls. In contrast,
these authors did not observe any differences for 5- and 8-week old mice (Alexeeff and Kilgore.
1983).
Nitschke et al. (1988b). a two-generation reproductive study in rats, Schwetz et 	, a
prenatal developmental toxicity study in rats and mice, and Hardin andManson (1980). a
reproductive/developmental study in rats using multiple exposure designs, did not identify
nervous system effects. However, these studies did not measure neurobehavioral outcomes and
also did not identify whether tissues of the nervous system were evaluated during
histopathological examinations.
There is no single animal model for the complex syndrome that constitutes ASD, although
animal study protocols that may approximate some aspects include evaluation of reciprocal
social communicative behavior or repetitive and stereotyped behavior. Animal data using these
protocols have not been identified for methylene chloride (Fetch et al.. 2019).
Mechanistic Data
Solvents are known to produce generalized CNS depression (Moser et al.. 2008). General
depressants may initially suppress inhibitory systems at low doses to produce excitation and lead
to a continuum of effects from excitation to sedation, motor impairment, coma, and ultimately
death by depression of respiratory centers (Moser et al.. 2008). Moser et al. (2008) discusses
several hypotheses regarding mechanisms related to generalized CNS depression but notes that
none are definitive. Across solvents, potency has been shown to be correlated with the olive
oil: water or octanol: water partition coefficients, suggesting possible disruption of the lipid
portions of cell membranes. CNS depression could result from membrane expansion or effects
on mitochondrial calcium transport. The effect may also be related to interactions with ligand-
gated ion channels and voltage-gated calcium channels, with specific gamma-aminobutyric acid
(GABA) type A, N-methyl-D-aspartate (NMDA) and glycine receptors possibly involved (Moser
et al.. 2008).
Page 265 of 753

-------
Mechanistic information specific to methylene chloride is described for primary nervous system
effects related to CNS depression including changes in locomotor activity as well as effects on
motor coordination and learning and memory. Bale et al. (2.011) reviewed data for methylene
chloride and other solvents and note that they may act on several molecular targets in the CNS,
likely through multiple mechanisms.
Some of the primary effects of methylene chloride are related to CNS depression and motor
incoordination and abnormal gait. Studies have shown that GABA and glutamate receptors in the
cerebellum may be involved in motor coordination and general CNS depression. Also, studies
with toluene indicate that the dopaminergic system may be involved in changes in locomotion
(Bale et al..: ). Methylene chloride has been shown to increase dopamine along with
serotonin in the medulla and increase GABA and glutamate in the cerebellum (Kanada et al...
1994). However, K anada et al. (1994) did not measure functional changes resulting from these
neurochemical changes. Therefore, EPA cannot make definitive conclusions about the
associations between these changes and CNS depression and motor changes. Bale et al. (2011)
also states that studies have not been conducted to evaluate the neurochemical basis for changes
in spontaneous activity for methylene chloride. Data suggest that increased COHb levels result in
CNS depression (Putz et al.. 1979) but doesn't fully explain the independent and possible
additive effect of methylene chloride because a weaker effect (or no effect) on the nervous
system was observed with administration of exogenous CO compared with methylene chloride
administration (Putz et al.. 1979; Winneke. 1974).
Changes in deoxyribonucleic acid (DNA) concentration and enzyme activities in the cerebellum
(Rosemerem et al.. 1986; Savolainen et al.. 1981) may be associated with changes in motor
activity and neuromuscular function. Among other endpoints, Savolainen (1981) measured
changes in succinate dehydrogenase (SDH) from exposure to methylene chloride. SDH is a
tricarboxylic acid cycle enzyme that is also part of the mitochondrial electron transport chain
(Quinlan et al.. i ). Savolainen (1981) reported decreased SDH in the cerebellum, which
coordinates motor activity. SDH levels recovered somewhat but still remained lower than
controls during a second week of exposure and after a week-long recovery period. Effects were
generally greater for a TWA concentration of 1000 ppm methylene chloride, which included 2
daily 1-hr exposures to 2800 ppm compared with a constant concentration of 1000 ppm
(Savolainen et a	). This greater effect may partly explain effects (e.g., respiratory
depression, death) experienced by humans after high acute exposures.
Alexeef and Kilgore (1983) showed that at 47,000 ppm, methylene chloride may affect learning
and memory as evidenced by a change in passive avoidance conditioning, and Kanada (1994)
showed that acetylcholine (ACh) levels were increased in response to methylene chloride and
Bale (2011) notes that memory and cognition deficits are thought to be due to decreased
cholinergic system functioning. The increase in ACh seen by Kanada (1994) could lead to
altered cognition as a response to inhibiting nuclear ACh receptors to maintain normal function
(Bale et al.. 2011). Alternately, decreases in learning and memory function may be affected by
decreased motor function and CNS depression (Bale et al.. ); because learning and memory
have not been routinely associated with methylene chloride and because the study (Alexeeff and
Kilgore j 983) that identified changes in learning and memory was conducted at a very high
concentration, it seems plausible that the effects from methylene chloride may be at least
partially related to CNS depression.
Page 266 of 753

-------
Decreased catecholamine in the caudate nucleus and decreased DNA content in the hippocampus
as a result of methylene chloride may also suggest possible learning and memory impairment
(Rosengren et at.. 1986; Fuxe et at. 1984) based on the location of these decreases. However, as
noted above, changes in learning and memory have been identified in only limited studies in
humans and animals.
Information is limited regarding the contribution of the parent compound, methylene chloride
versus metabolite(s) to nervous system effects. Methylene chloride has been shown to distribute
to the brain with higher concentrations than other tissues (Nae/Aeet. 2.008b). Also, increased
COHb levels can result in CNS depression e.g., (Putz et at.. 1979) but a weaker effect or no
effect was observed with exposure to exogenous CO compared with methylene chloride
suggesting that at these concentrations COHb is not the only moiety leading to the effects and
may play a minor role (Putz et at.. 1979; Winneke. 1974). CO and subsequently COHb may only
result in significant neurobehavioral changes at higher concentrations (NAC/AEGL. 2008a).
3.2.3.1.5 Reproductive and Developmental Effects
In addition to the epidemiological studies related to nervous system effects noted previously,
EPA identified several other relevant epidemiological studies of reproductive and developmental
effects and identified effects, including developmental neurotoxicity (which are described in
section 3.2.4.1.4), in some studies. EPA did not locate mechanistic data specific to reproductive
and developmental toxicity.
Humans
Kinder et at. (201 H was identified during the recent literature search. These authors evaluated
the association between industrial air releases of chlorinated solvents (including methylene
chloride) and birth defects in children. Cases and controls were mothers recruited from the same
regions in Texas and birth defects identified from the Texas Birth Defects Registry. Exposure
was estimated based on proximity of mothers' residences to emissions and the quantity of
methylene chloride released. Differences in certain characteristics such as race, ethnicity and
education were controlled for in the statistical analyses. Although methylene chloride was not
associated with most birth defects, statistically significant relationships were observed among
mothers 35 years or older for two defects: any oral cleft defect (OR = 1.38, with 95% CI: 1.14,
1.67) and cleft lip with or without cleft palate (OR = 1.53, with 95% CI: 1.21, 1.93). The authors
also reported that significant linear trends were observed for the association between methylene
chloride and isolated conotruncal heart defects for offspring of mothers of all ages (OR for the
highest exposure risk value was 1.56, 95% CI: 1.05, 2.32). Selection bias appeared to be low,
exclusions from the study were limited and the potential for exposure misclassification was
considered to be low. In evaluating outcomes of interest, there is some uncertainty regarding
whether exposure occurred during the first trimester; some exposure measurement error could if
there is variability in methylene chloride during pregnancy. Because the models did not account
for co-exposures to other chlorinated solvents or other chemicals, the association between
individual chemicals and the birth outcomes is less certain. In other studies (e.g., the ASD
epidemiological studies), methylene chloride was sometimes highly correlated with other
compounds. Indeed, some of the other chemicals measured in separate models in this study were
Page 267 of 753

-------
associated with some of the same birth defects more often or showed associations larger in
magnitude than methylene chloride. The data quality rating for this study is medium.
Other studies evaluated reproductive/developmental effects. Bell c	examined the
association between estimated methylene chloride air concentrations in the community
surrounding the Eastman Kodak triacetate film facility in Rochester, New York and birth weight
of children born to mothers in the surrounding population. Air dispersion modeling was used to
estimate exposures; the highest predicted average methylene chloride air concentration in the
studied community was 50 |ig/m3. Birth certificates were obtained for the years 1976-1987.
Because the number of births in non-whites was small, the analysis was restricted to the white
population. At the levels of methylene chloride in this study, no significant adverse effect was
found between any combination of methylene chloride exposure levels and birthweight.
Comparing participants residing in the census tracts with the highest exposure group to the
census tracts with no predicted exposure, the OR was 1.0 (95% CI: 0.81, 1.24). The authors note
that the exposure estimates from the air dispersion modeling were higher than monitored values
in the area. Also, the assignment of methylene chloride exposures to each birth was made using
the predominant value of the isopleth for a census tract, and this could have led to some exposure
misclassification. This study received a data quality rating of high.
Taskinen et al. (1986) examined spontaneous abortion rates in female workers employed in
pharmaceutical factories in Finland. In addition to examining overall rates, Taskinen et al. (1986)
conducted a case-control analysis to estimate association between spontaneous abortions and
methylene chloride, a solvent commonly used in the pharmaceutical industry, as well as other
chemicals. Forty-four cases and 130 controls were identified. For methylene chloride exposure,
the prevalence of exposure was 29% and 14% in the cases and controls, respectively. The OR
was 2.3 (95%) CI: 1.0-5.7; p = 0.06); this OR didn't appear to account for co-exposure and
possible confounders although controls were matched on maternal age. Less precise results
(higher p values) that were similar in magnitude were noted for other solvents (OR range: 1.6 to
3.2). The OR for exposure to four or more solvents (OR: 3.5, p = 0.05) was greater than for one
to three solvents (OR: 0.8, p = 0.74). EPA gave this a data quality score of low based on several
measures including method of identifying exposures, temporality, covariate adjustment and
characterization and confounding from co-exposures.
Male reproductive effects were investigated in a couple of case series reports. Kelly et al. (1988)
cited in U.S. EPA ( ) studied 34 men working in the automotive industry who self-referred to
a health clinic. Eight men who worked as bonders and routinely dipped hand-held pads (and
didn't always use gloves) in buckets of methylene chloride had symptoms of testicular and
epididymal tenderness, and sperm counts were 25 xl06/cm3 (oligospermia can be defined as 20 x
106/cm3). Despite not using contraception, the men had not conceived any children (and one
reported a miscarriage) - conclusions about these results are not possible because there was no
comparison group. Wells et al. (1989). however, reported a mean sperm count of 54 x 106/cm3 in
eleven furniture refinishers (none with oligospermia), slightly higher than the population value of
47 x 106/cm3.
Animals
Page 268 of 753

-------
Animal studies show reproductive/developmental effects in some studies but not others. A two-
generation inhalation toxicity study revealed no significant effects on fertility, litter size,
neonatal survival, histopathological changes or growth rates in either generation (F1 or F2) of
rats exposed up to 1,500 ppm methylene chloride (Nitschke et at.. 1988b).
Raje et al. (1988) found some evidence of a decrease in fertility index after male mice were
exposed to 144 and 212 ppm for 2 hrs/day for 6 weeks and then mated with unexposed females;
fertility index values were 80% at each concentration compared with 95% at 0 and 100 ppm, but
not statistically significant (overall X2 p-value of 0.27). U.S. EPA (2011) conducted some
statistical analyses - the trend test using a Cochran-Armitage exact trend test yielded a one-sided
p-value of 0.059. Using the Fisher's exact test, one-sided p-value was 0.048 when comparing the
combined 144 and 212 ppm groups with the 0 and 100 ppm groups; U.S. EPA (2011) suggested
a NOAEC of 100 ppm (103 ppm) and lowest observable adverse effect concentration (LOAEC)
of 150 ppm (144 ppm). This data quality rating is medium.
Pregnant mice and rats were exposed to 1,250 ppm methylene chloride for 7 hours/day during
gestation days 6-15 (Schwetz et al.. 1975) and exhibited certain skeletal variants after exposure.
In rats, the incidence of ribs or spurs was decreased and incidence of delayed ossification of
sternebrae was increased (p < 0.05 for both). Mice exhibited an increased number of litters with
pups that had a single extra center of ossification in the sternum (p < 0.05) (S chwetz et al.. 1975).
Hardin and Man son (1980) did not identify statistically significant changes in the incidence of
external, skeletal or soft-tissue anomalies in fetuses of female Long-Evans hooded rats exposed
to 4500 ppm methylene chloride before and/or during gestation. However, decreased fetal body
weights (by 9-11%) were observed when dams were exposed during gestation only (days 1-17)
or both before (12-14 days) and during gestation (1-17 days) (p < 0.05 by two-way ANOVA).
Results of oral animal studies did not identify reproductive or developmental effects. Narotsky
and Kavlock (1995) did not observe effects on pup survival, resorptions or weight after pregnant
F344 rats were administered doses as high as 450 mg/kg-day on gestational days (GDs) 6-19,
although maternal weight was decreased. No effects on reproductive performance endpoints
(fertility index, number of pups per litter, pup survival) were found in studies in male and female
Charles River CD rats administered methylene chloride via gavage for 18 weeks and
administered doses up to 225 mg/kg-day with subsequent exposure to offspring for 13 weeks
(General Electric Company. 1976).
Mechanistic Data
Other than studies measuring general modes of action of methylene chloride (e.g., oxidative
stress, genotoxicity, increased COHb), EPA did not identify studies that link reproductive and
developmental effects with specific cellular mechanisms.
3.2.3.1.6 Irritation/Burns
Human and animal data that evaluated or reported irritation and burns of skin, eyes, respiratory
tract and gastrointestinal tract after use of methylene chloride are summarized below. EPA
summarized several human case reports. EPA qualitatively evaluated a human controlled
experiment (in consideration of using it for CNS effects from acute/short-term exposure - see
Section 3.2.4.1.4); however, other studies were not evaluated for quality.
Page 269 of 753

-------
After two hours of exposure to 986 ppm methylene chloride in air, volunteers reported no
symptoms of eye, nose or throat irritation (Stewart et at.. 1972.). This study was evaluated
qualitatively (EPA. 2019f) and although the lack of blinding suggests low confidence in the
subjective symptom results, the subjects would be likely to over-report (rather than under-report)
symptoms if they knew they were exposed to methylene chloride.
Anundi et al. (1993) did report irritation to the eyes and upper respiratory tract among graffiti
removers in an underground station in Sweden. The workers had been on the job between 3
months and 4.7 years. TWA exposures of 18-1,200 mg/m3 (5-340 ppm) were measured in this
study and reported exposures to other chemicals were much lower and found in only a limited
number of samples (Anundi et al... 1993).
A 21-year old male working in a furniture stripping shop had first and second-degree burns from
direct contact with the liquid after being found slumped over a tank of methylene chloride (Hall
andRuMack. 1990). Direct contact of eyes with methylene chloride in a workplace accident
resulted in severe corneal burns; duration of contact is not known. Furthermore, air
concentrations of 2300-7200 ppm resulted in irritation after 5-8 minutes (Hall and Rumack.
1990). Other case reports also indicate that methylene chloride can cause second and third degree
burns upon direct contact with the liquid (Wells and Waldron. 1984).
In one suicide case, ingestion of paint remover containing 75-80% methylene chloride, resulted
in death from corrosion of the gastrointestinal tract (Hughes and Tracev. 1993). The individual
was exposed to methanol as well, which can cause respiratory (e.g., nasal) irritation (EPA.
2013c).
Small increases in corneal thickness and intraocular tension reported after exposure of rabbits to
vapors of > 490 ppm methylene chloride were reversible within 2 days after exposure ceased.
Following direct eye contact with methylene chloride (0.1 mL), rabbits exhibited inflammation
of the conjunctivae and eyelids and increases in corneal thickness and intraocular tension. The
effects were reversible within 3 to 9 days (Ballantvne et al.. 1976). NTP (1986) notes that
inflammation and metaplasia in nasal cavities of rats exposed to methylene chloride may have
been due to irritation.
Between 2007 and 2016, the Washington Poison Center in King County, WA received 150 calls
related to methylene chloride. Thirty-six dermal and ocular cases required follow-up; seven were
of moderate severity and the rest were minor. Among these cases, there were nine cases of burns
(five were moderate) and three cases of corneal abrasion (two were moderate). Irritation and pain
were identified in multiple reports with red eye and skin edema identified in some cases (Fisk
and Whittaker. 2.018).
3.2.3.2 Cancer Hazards
EPA identified several epidemiological studies published subsequent to the 2011 IRIS
assessment (U.S. EPA. 2011) as well as one animal bioassay. EPA evaluated these studies as
well as epidemiological and chronic animal bioassays from the IRIS assessment. The overall data
evaluation ratings for all studies evaluated for data quality are included in the tablesthroughout
Page 270 of 753

-------
this section. EPA also summarized genotoxicity data, which were evaluated for data quality.
Other mechanistic studies are summarized but were not evaluated.
3.2.3.2.1 Carcinogenicity
The potential carcinogenicity of methylene chloride has been evaluated in a number of human
epidemiological studies and animal cancer bioassays. These data are summarized by target tissue
(liver, lung, breast, hematopoietic, brain/CNS and other neoplasms) below.
Liver Cancer
The human epidemiological data are inconclusive as to the association between liver and biliary
tract cancer and methylene chloride exposure (Section 3.2.3.1.2). Epidemiological data are
limited to four occupational cohort mortality studies of workers involved in CTA fiber (Gibbs et
ai. 1996; Lanes et ai. 1993) and film base production (Tom en son. 2011; Heame and Piter.
1999) with contradictory findings, and a small cohort study of incident cholangiocarcinoma in
Japanese offset-proof print workers that did not show an association with methylene chloride
exposure (Kumagai et at.. 2016).
Animal data (Also et at.. 2014a; NTP. 1986) provide clear and consistent evidence that
methylene chloride induces liver tumors in male and female mice (Tables 3-6 and 3-7).
Significant increases in the incidences of hepatocellular adenoma or carcinoma were observed in
male and female B6C3F1. and Crj:BDFl mice exposed via inhalation (Aiso et at.. 2014a; NTP.
1986). Male mice exposed by inhalation also exhibited a significant increase in the incidence of
hepatic hemangiomas in the study by Aiso (2014a). and both male and female mice in this study
showed significant exposure-related trends in the incidences of combined hemangiomas and
hemangiosarcomas. Increased incidences of hepatocellular adenoma or carcinoma were also
observed in male B6C3F1. mice exposed via drinking water (Serota et at.. 1986b; Hazteton
Laboratories. 1983). In rats there have been suggestive findings related to liver tumors, with a
significant increase in the incidence of hepatic neoplastic nodules or hepatocellular carcinomas
in female F344 rats after drinking water exposure (Serota et al.. 1986a) and a significant dose-
related trend in the incidence of hepatocellular adenoma or carcinoma in male F344/DuCrj rats
after inhalation exposure (Aiso et al.. ).
Table 3-5. Selected Effect Estimates for Epidemiological Studies of Liver Cancers
Reference
Type
SMR/
IKK
95%
IX L
95%
1 CI.
Study Quality
Kvalualion
Liver and biliary tract
Lanes et al. (1993) (men and women)
SMR
2.98
0.81
7.63
Medium
Lanes et al. (1993) (men and women: > 10
yrs employment, > 20 yrs since first
employment)
SMR
5.83
1.59
14.92
Medium
Hearne and Pifer (1999) (men)
SMR
0.42
0.01
2.36
High
Gibbs et al. (1996) (men)
SMR
0.81
0.02
4.49
High
Page 271 of 753

-------
Table 3-5. Selected Effect Estimates for Epidemiological Studies of Liver Cancers
Gibbs et al. (1996) (women)
SMR
(no exposed cases)

Tomenson et al. (2011) (men)
SMR
(no exposed cases)
Medium
Cholangiocarcinoma
Kumagai et al. (2016)
IRR
0.45 0.11 1.77
Medium
SMR = Standardized Mortality Ratio
IRR = incidence rate ratios
LCL = lower confidence limit
UCL = upper confidence limit
Table 3-6. Summary of Significantly Increased Liver Tumor Incidences in Inhalation
Studies of Methylene Chloride
Male Mice
Conccnlration (mg/iir*)
0 1 35(H) 1 7000 1 14.000
Aiso et al. (2014a) (BDF1)
Hepatocellular adenoma
10/50A
13/50
14/50
15/50
Hepatocellular carcinoma
10/50A
9/50
14/50
20/50*
Hepatocellular adenoma or carcinoma
15/50A
20/50
25/50*
29/50*
Hepatic hemangioma
0/5 0A
4/50
3/50
5/50*
Hepatic hemangioma or hemangiosarcoma
1/50A
4/50
4/50
6/50
NT I' (1986) (B6C3F1)
Hepatocellular adenoma
10/50
NT
14/49
14/50
Hepatocellular carcinoma
13/50A
NT
15/49
26/50*
Hepatocellular adenoma or carcinoma
22/50A
NT
24/49
33/50*
l''cmalc Mice
( oneon)ration (mg/iir*)
0 1 3500 1 7000 1 14.000
Aiso et al. (20j_kj) (F344/DuCrj)
Hepatocellular adenoma
1/50A
7/50*
4/49
16/50*
Hepatocellular carcinoma
1/50A
1/50
5/49
19/50*
Hepatocellular adenoma or carcinoma
2/5 0A
8/50*
9/49*
30/50*
Hepatic hemangioma or hemangiosarcoma
3/50A
2/50
0/49
7/50
NTP (1986) (F344)
Hepatocellular adenoma
2/5 0A
NT
6/48
22/48*
Hepatocellular carcinoma
1/50A
NT
11/48
32/48*
Page 272 of 753

-------
Table 3-6. Summary of Significantly Increased Liver Tumor Incidences in Inhalation
Studies of Methylene Chloride
Hepatocellular adenoma or carcinoma
3/50A
NT
16/48*
40/48*
Male Kills
( oneon)ration (mg/iir*)
0 1 35(H) 1 7000 1 14.000
Aisoetal. (2014a) (F344/DuCri)
Hepatocellular adenoma or carcinoma
1/50A
0/50
2/50
3/50
Study Quality Evaluation
Aiso et al. (2014a)
High
NTP (1986)
High
ASignificant dose-related trend (p<0.05)
*Significant pairwise comparison (p<0.05)
NT = not tested
Page 273 of 753

-------
Table 3-7. Summary of Significantly Increased Liver Tumor Incidences in Oral Studies of
Methylene Chloride
Hazleton Labs (I 
-------
In animal studies, methylene chloride produced large, statistically significant increases in lung
tumor incidences in male and female mice exposed by inhalation (Also et al. 2014a; NTP.
1986).
There was also some evidence for production of lung tumors in mice by oral exposure to
methylene chloride. Maltoni et al. (1988) reported a nonsignificant dose-related trend for higher
incidences of pulmonary adenomas in male, but not female, mice in an oral gavage study that
was, however, terminated at 64 weeks due to high mortality. A 2-year drinking water study did
not find any increase in lung tumor incidence in male or female mice (Serota et a 5b). Lung
tumors were not increased by methylene chloride in rats or hamsters by inhalation or oral
exposure (Maltoni et al.. 1988; Nitschke et al.. 1988a; NTP. 1986; Serota et a 5a; Burek et
al.. 19841
Table 3-8. Selected Effect Estimates for Epidemiological Studies of Lung Cancers
Reference
Type
SMR/
OK
95%
I.CI.
95%
rci.
Study
Quality
Evaluation
Lanes et al. (1993) (men and women)
SMR
0.80
0.43
1.37
Medium
Hearne and Pifer (1999) (men)
SMR
0.75
0.49
1.09
High
Tom en son et al. (2011) (men)
SMR
0.48
0.31
0.69
Medium
Gibbs et al. (1996) (men)
SMR
0.55
0.31
0.91
High
Gibbs et al. (1996) (women)
SMR
2.29
0.28
8.29
High
Vizcava et al. (2013)
OR
1.1
0.6
1.9
Medium
Mattei et al. (2014) (women)
OR
1.38
0.74
2.57
Medium
Siemiatvcki et al. (1991) (all lung)
OR
3.8
1.2
12.0
Medium
Siemiatycki et al. (1991) (squamous cell)
OR
4.0
0.9
17.3
Medium
AORs are for substantial exposure. Siemiatycki et al. (1.991.) also presents ORs for 'any' exposure, which are lower than for
substantial exposures. Also, the LCL and UCL are the 90%ile values, not 95%ile values.
Table 3-9. Summary of Significantly Increased Lung Tumor Incidences in Inhalation
Studies of Methylene Chloride
Male Mice
Concent rat ion (mg/iir*)
0 1 35(H) 1 7000 1 14.000
Aiso et al. (2014a) (BDF1)
Bronchoalveolar adenoma
7/50A
3/50
4/50
14/50
Bronchoalveolar carcinoma
1/50A
14/50*
22/50*
39/50*
Bronchoalveolar adenoma or carcinoma
8/5 0A
17/50*
26/50*
42/50*
NTP (1986) (B6C3F1)
Page 275 of 753

-------
Table 3-9. Summary of Significantly Increased Lung Tumor Incidences in Inhalation
Studies of Methylene Chloride
Bronchoalveolar adenomas
3/50A
NT
19/50*
24/50**
Bronchoalveolar carcinomas
2/5 0A
NT
10/50*
28/50*
Bronchoalveolar adenomas or carcinomas
5/50A
NT
27/50*
40/50*
I'dnale Mice
0
35(H)
7000
14.000
Aiso et al. (2014a) (BDF1)
Bronchoalveolar adenomas
2/5 0A
4/50
5/49
12/50*
Bronchoalveolar carcinomas
3/50A
1/50
8/49
20/50*
Bronchoalveolar adenomas or carcinomas
5/50A
5/50
12/49*
30/50*
Bronchoalveolar adenoma or carcinoma or
adenosquamous carcinoma
5/50A
5/50
12/49*
30/50*
NT I' (1986) (B6C3F1)
Bronchoalveolar adenomas
2/5 0A
NT
23/48*
28/48*
Bronchoalveolar carcinomas
1/50A
NT
13/48*
29/48*
Bronchoalveolar adenomas or carcinomas
3/50A
NT
30/48*
41/48*
Study Quality Evaluation
Aiso et al. (2.014a)
High
NTP (1986)
High
ASignificant dose-related trend (p<0.05)
*Significant pairwise comparison (p<0.05)
Breast Cancer
The available epidemiological data on breast cancer, including two occupational cohort mortality
studies, a prospective population cohort study and a case-control study, provide inconclusive
results. The mortality rate for breast cancer was less than unity in a cohort of CTA fiber
production workers (Lanes et at.. 1993). but an elevated HR was reported among Air Force base
employees (Radican et at.. 2008). Because exposure at the Air Force base was predominantly
trichloroethylene, the CTA cohort provides greater specificity for methylene chloride. A case
control study by Cantor (1995) showed increased ORs for breast cancer among women with the
highest exposure probability; however, this study estimated exposure based on occupation
reported on death certificates, instead of detailed job history obtained by in-person or proxy
interview. Garcia (2015) found no increased risk when using modeled outdoor air concentrations
from emissions (EPA NATA). A summary measure of multiple pollutants also did not yield an
increased HR (HR = 1.05).
Animal data provide some evidence that methylene chloride induces mammary tumors in male
and female rats following inhalation exposure. These incidences of mammary gland
Page 276 of 753

-------
fibroadenoma were significantly increased in male F344/DuCrj rats (Also et al..! ) and
female F344 rats (NTP. 1986) exposed to methylene chloride via inhalation. Exposure-related
trends were reported for both sexes. The incidence of this tumor was higher, and occurred at a
lower concentration, in female rats compared to males. Significant increases were also reported
in male rats for the combined incidences of mammary gland fibroadenoma or adenoma (Also et
al.. 2014a) and adenoma, fibroadenoma or fibroma (NTP l86). In female rats, the combined
incidence of adenoma, fibroadenoma, or adenocarcinoma was increased (NTP. 1986). A
significant dose-related trend was observed in the incidence of benign mammary tumors in male
Sprague-Dawley rats (Burek et al.. 1984). Chronic inhalation studies in mice and chronic oral
studies in rats and mice did not demonstrate an increased incidence of mammary tumors.
Table 3-10. Selected Effect Estimates for Epidemiological Studies of Breast Cancers
Reference
Type
SMR/
OK/
Ilk
95%
I.CI.
95%
1 C L
Study
Quality
Evaluation
Lanes et al. (1993)
SMR
0.54
0.11
1.57
Medium
Radican et al. (2008)
HR
2.36
0.98
5.65
Medium
Cantor et al. (1995) white women
OR
1.17
1.1
1.3
High
Cantor et al. (1995) black women
OR
1.46
1.2
1.7
High
Garcia et al. (2015)
HR
1.04
0.96
1.13
High
Table 3-11. Summary of Significantly Increased Mammary Tumor Incidences in
Inhalation Studies of Methylene Chloride



Concentration (ing/nr*)

Male Uats
0

35(H)
7000
14.000
Aiso et al. (2014a) (F344/DuCri)
Mammary gland fibroadenoma
1/50A
2/50
3/50
8/50*
Mammary gland fibroadenoma or
adenoma
2/5 0A
2/50
3/50
8/50*
Mammary gland fibroadenoma or
adenoma or adenocarcinoma @
3/50A
2/50
3/50
8/50
NTP (1986)
(F344)


Mammary gland subcutaneous tissue
fibroma or sarcoma #
1/50A
1/50
2/50
5/50
Mammary gland fibroadenoma
0/5 0A
0/50
2/50
4/50
Mammary gland or subcutaneous
tissue adenoma, fibroadenoma, or
fibroma
1/50A
1/50
4/50
9/50*
Page 277 of 753

-------
Table 3-11. Summary of Significantly Increased Mammary Tumor Incidences in
Inhalation Studies of Methylene Chloride
Bureketal. (1984) (Svrague-Dawlev)


('oncenlralion (mg/iir*)


0
1800
5300
12.000
Benign mammary tumors
7/92A
l^5
7/95
14
I'dnale Kills
0
( oncenlralion (nig/nr*)
3500 1 7000
14.000
. l/.\o cl <
//. ( ) (i.
44 I >//( 'rj)


Mammary gland fibroadenoma
7/50A
7/50
9/50
14/50
Mammary gland fibroadenoma or
adenoma
7/50A
8/50
10/50
14/50
Mammary gland fibroadenoma or
adenoma or adenocarcinoma @
7/50A
9/50
10/50
14/50
N/'P (1986) (F344)
Mammary gland fibroadenoma
5/50A
11/50*
13/50*
22/50*
Mammary gland adenoma,
fibroadenoma, or adenocarcinoma #
6/5 0A
13/50
14/50*
23/50*
Nitschke ci
//. ( > (S/>rai*iic-rki\vIcyi



('oncenlralion (ing/nr*)


0
ISO
700
IS00
Benign mammary tumors
52/70
58 70
M 7o:;:
55/70
Study Quality Evaluations
Aiso et al. (2014a)
High
Burek et al. (1984)
High
Nitschke et al. (1988a)
High
NTP (1986)
High
ASignificant dose-related trend (p<0.05)
*Significant pairwise comparison (p<0.05)
@ Adenocarcinomas were observed in 0, 2, 1 and 0 female rats at 0, 3500, 7000 and 14,000 mg/m3; no malignant
tumors were seen in male rats
# Sarcoma incidence was observed in 1 male at the highest concentration (14,000 mg/m3); Adenocarcinomas/
carcinomas were observed in 1, 2, 2 and 0 female rats at 0, 3500, 7000 and 14,000 mg/m3
Hematopoietic Cancer
Page 278 of 753

-------
As presented in Table 3-12, the association between various hematopoietic cancers and exposure
to methylene chloride has been examined in occupational cohort mortality studies (Tomenson.
2011; Radican et at.. 2008; Heame and Pifer. 1999) and population-based case control studies
(Christensen et at.. 2013; Morales-Suarez-Varela et at.. JO IBarry et ot .aM i_, , <4d et al.
2010; Wang et at... 2009; Costantini et at.., 2008; Seidler et at... 2007; Mitigi et at... 2006).
Findings were inconsistent and inconclusive for most categories of hematopoietic cancers
(leukemia, multiple myeloma, Hodgkin lymphoma, non-Hodgkin lymphoma (NHL)). However,
ORs for B-cell subtypes of NHL were consistently increased in three case-control studies that
evaluated this tumor type (Barry et al.. 2011; Seidler et al.. 2007; Mitigi et at... 2006). For
example, Mitigi et al. (2006) identified an OR for B cell NHL of 3.2, which was higher than the
ORs for all other chemicals studied. Despite these more consistent results for B-cell NHL, the
studies did not control for other chemical exposures. In addition, there was evidence (e.g., for
Mitigi et at. (2006) that some chemical exposures were highly correlated and other chemicals
were also associated with the outcomes of interest, making it difficult to attribute effects to
methylene chloride alone. NTP (1986). Mennear et al.(1988) (which is the published version of
NTP (1986)) and Aiso et al. (2014a) each reported an increased incidence of mononuclear cell
leukemia in female (but not male) rats (Table 3-13). However, the incidences did not exhibit
monotonic dose-response relationships.
Table 3-12. Selected Effect Estimates for Epidemiological Studies of Hematopoietic
Cancers
Reference
Type
SMR/
OR/
HR
95%
LCL
95%
UCL
Study Quality
Evaluation
Non-Hodgkin Lymphoma (NHL)
Hearne and Pifer ( ))
SMR
0.49
0.06
1.78
High
Radican et al. (2008) (men)
(women)
HR
2.02
0.76
5.42
High
No observed NHL
deaths
Miligi et al. (2006)
OR
1.7
0.7
4.3
High
Wang et al. (2009)
OR
1.5
1.0
2.3
Medium
Christensen et al. (2013)
OR
0.6
0.2
2.2
Medium
B-cell NHL
Seidler et al. (2007)
OR
2.7
0.5
14.5
High
Barry et al. (2011)
(diffuse large B-cell lymphoma)
OR
2.10
1.15
3.85
High
Miligi et al. (2006)
(small lymphocytic lymphoma*)
OR
3.2
1.0
10.1
High
T-cell NHL (Mycosis Fungoides)
Morales-Suarez-Varela et al. (20! 3) (women)
OR
2.90
0.45
15.72
High
Page 279 of 753

-------
Table 3-12. Selected Effect Estimates for Epidemiological Studies of Hematopoietic
Cancers
Hodgkin Lymphoma
Hearne and Pifer (1999)
SMR
1.82
0.20
6.57
High
Seidler et al. (2007)
OR
0.7
0.2
3.6
High
Multiple Myeloma
Hearne and Pifer ( ))
SMR
0.68
0.01
3.79
High
Radicati et al. (2008) (men)
(women)
HR
2.58
0.86
7.72

No observed multiple
myeloma deaths
Gold et al. (2010)
OR
2.0
1.2
3.2
Mediuma
Leukemia
Hearne and Pifer ( ))
SMR
2.04
0.88
4.03
High
hoechst celanese cc (Maryland
SMR
1.9
0.51
4.8
Medium
cohort)
hoechst celanese cc (South Carolina
SMR
0.90
0.02
3.71
Medium
cohort)
Tomenson et al. (2011)
SMR
1.11
0.36
2.58
Medium
Costantini et al. (2008)
OR
0.5
0.1
2.3
Medium
Costantini et al. (2008)
(chronic lymphocytic leukemia*)
OR
1.6
0.3
8.6
Medium
Infante-Rivard et al. (2005)
OR
3.22
0.88
11.7
High
*These two diagnoses differ only in how they present (leukemia or lymphoma presentation).
"Downgraded from High (1.6) due to small numbers of exposed cases and controls
Table 3-13. Summary of Mononuclear Cell Leukemia Incidences in Inhalation Studies of
Methylene Chloride
Male Kills
0
( Ol
3500
icenlralion (n
7000
ig/ni"')
14.000
Aiso et al. (2014a) (F344/DuCri)
3/50
3/50
8/50
4/50
YI P ( )(| 344 \)
1'cinalc Uals
34 5<)
0
2o 5<>
Col
3500
32 5<)
icenlralion (n
7000
35 5<>
i/m-5)
14.000
Aiso el al ( )(l'344 l)u( i j)
2 5i)
4 5i)
S 5<):;:
7/50
Page 280 of 753

-------
Table 3-13. Summary of Mononuclear Cell Leukemia Incidences in Inhalation Studies of
Methylene Chloride
NTP (1986) (F344/N)
17/50
17/50
23/50#
23/50#
Study Quality Evaluations
Aiso et al. (2014a)
High
NTP (1986)
High
indicates statistically significant expo sure-related trend
indicates statistically significant difference from concurrent control.
"Statistically significant difference from concurrent control by life table test.
Brain and CNS Cancer
Epidemiological data on brain and CNS tumors after methylene chloride exposure are
inconclusive (see Table 3-14). Two occupational cohort studies ("Tom en son. 201 I; Uearne and
Pifer. 1999) reported non-significantly elevated SMRs for brain and CNS cancers. Two case-
control studies reported slightly increased ORs (Cocco et at.. 1999; Heineman etai. 1994). The
OR (1.2) reported by Cocco (1999) was statistically significantly increased. This study used an
imprecise exposure assessment based on occupation reported on each subject's death certificate,
and it is not known how the OR would change with more precise exposure information. Two
case-control studies with more robust exposure assessments (Ruder et at.. 2.013; Neta et at..
2012) did not show increases in the ORs for two of the most common brain cancers (gliomas and
meningiomas). The only animal evidence of brain or CNS tumors is the observation of low
incidences of rare astrocytomas in methylene chloride-exposed Sprague-Dawley rats with
incidences of 0, 1, 2, 1 (per 70 males/group) at 0, 50, 200, or 500 ppm (0, 175, 702, or 1755
mg/m3) (Nitschke et at.. 1988a). No brain or CNS tumors were observed in F344 rats or in mice
exposed by inhalation to higher concentrations (Also et at.. 2014a; N1 6).
Table 3-14. Selected Effect Estimates for Epidemiological Studies of Brain and CNS
Cancers
Reference
Type
SMR/OR/
HR
95%
LCL
95%
UCL
Study
Quality
Evaluation
Tumor type not specified
Hearne and Pifer ( )) (New
York)
SMR
2.16
0.79
4.69
High
Tomenson et al. (2011) (U.K.)
SMR
1.83
0.79
3.60
Medium
Heineman et al. (1994) (U.S.)
OR
1.3
0.9
1.8
Medium
Cocco etal. (1999) (U.S.)
OR
1.2
1.2
1.3
Medium
Meningioma
Cocco etal. (1999) (U.S.)
OR
1.2
0.7
2.2
Medium
Page 281 of 753

-------
Table 3-14. Selected Effect Estimates for Epidemiological Studies of Brain and CNS
Cancers
Netaetal. (: )(U.S.)
OR
1.6
0.7
3.5
High
Glioma
Netaetal. (2012) (U.S.)
OR
0.8
0.6
1.1
High
Ruder etal. (2013) (U.S.)
OR
0.8
0.66
0.97
High
Other Cancers
Epidemiological studies provide limited data regarding other cancers. Carton et al. Q ),
assigned a data quality score of medium, found no association between methylene chloride
exposure and risk of squamous cell carcinoma of the head and neck in a case-control study of
women in France. Dosemeci et al. (1999) found no increased risk of renal cell carcinoma in a
population case-control study in Minnesota from exposure to methylene chloride estimated based
on job matrices; this study was given a data quality rating of medium. Purdue et al. (2016)
presents results of a sub-study within the population case-control U.S. Kidney Cancer Study and
did not identify a statistically significant increase in kidney cancer. The ORs in this study for
lower exposure probability groups were 1.2 (95% CLO.6-1.4 in the lowest group) and the OR for
the highest exposure probability group was 0.9 (95% CI: 0.6-1.6). Thus, no trend regarding
increased risk was identified for the higher likely exposure group. Purdue et al (2.016) received a
high (1.4) data quality rating. Siemiatvcki (19911 in a case-control study, identified an increased
risk of rectal cancer (OR = 4.8; 90% CI: 1.7-13.8) among males aged 35-70 in the Montreal area
identified as having significant exposure to methylene chloride (using a significance level of p =
0.10). This study received a data quality rating of medium.
Studies of other cancers in mice or rats exposed by inhalation reported increased incidences or
dose-related trends in the incidences of adrenal gland pheochromocytomas, subcutaneous
fibromas or fibrosarcomas, and endometrial tumors (Also et al.. 2014a): mesotheliomas (Also et
al.. 2014a: NTP. 1986): hemangiomas or hemangiosarcomas (NTP. 1986): or salivary gland
sarcomas (Burek et al.. 1984). In general, these tumors occurred at low frequency and were not
consistent across studies, species, or sexes, and the findings, therefore, are considered equivocal.
3.2.3.2.2 Genotoxicity and Other Mechanistic Information
Genotoxicity
Methylene chloride has been tested for genotoxicity in both in vivo and in vitro systems and in
mammalian and non-mammalian organisms. The vast majority of these studies received high
data quality ratings, a few received medium scores and a few had unacceptable ratings. The
following paragraphs summarize these results and Appendix K presents detailed tables of results
for the high and medium quality studies. The supplemental file Data Quality Evaluation of
Human Health Hazard Studies - Animal and In Vitro Studies (EPA. 2.019u) presents the data
quality ratings for all studies, both acceptable and unacceptable.
Page 282 of 753

-------
Positive results have generally been identified in systems that exhibit GST activity, specifically
GSTT1, indicating that metabolites of the GST are likely responsible for the tumorigenic
activity. Information indicates S-(chloromethyl)glutathione as most likely to result in genotoxic
damage, but DNA damage resulting from formaldehyde, another metabolite of methylene
chloride via the GST pathway, is also possible ([ \ V	).
Thier et al. (1998) cited by U.S. EPA (2011) found species' specific liver GSTT1 isozyme
activity after methylene chloride exposure to be ordered as follows (from highest to lowest):
mice, rats, human high and low conjugators, hamsters and human non-conjugators. When
comparing metabolism more generally by the GST pathway (irrespective of isozymes) in liver
and lung tissues, mice also are more active than rats, humans and hamsters (	1011).
However, human high conjugator GSTT1 activity in erythrocytes was the same as male mouse
liver activity and 61% of the female mouse liver activity. These relative activities may be the
reason for differences in genotoxicity among species as indicated below.
Increased frequencies of micronuclei and DNA damage were found in peripheral blood
lymphocyte or leukocyte samples from workers exposed to methylene chloride (Zeliezic et al..
2016V
Studies in mice exposed to methylene chloride showed significant increases in chromosomal
aberrations in the lung (Allen et al.. 1990); micronuclei in peripheral erythrocytes (Allen et al...
1990); and DNA damage in the liver, lung, and peripheral lymphocytes (Sasaki et al.. 1998b;
Casanova et al.. 1996; Graves et ai C S; Graves et al.. 1994b; Casan \ i ^ .i. C	u i:
al.. 1990). No DNA damage or increased gene mutations were observed in the livers of gpt delta
mice after 4 weeks of inhalation exposure to 800 ppm (Suzuki et al.. 2014). This was a lower
exposure concentration compared with the levels inducing DNA strand breaks (> 2000 ppm) or
increased tumor incidences. It is possible that CYP2E1 metabolism was not saturated at the
lower concentrations, limiting the formation of DNA-reactive GST metabolites.
Fewer in vivo data are available for rats, but available information shows positive evidence for
DNA SSBs in rat liver after exposure to methylene chloride (Kitchin and Brown. 1989). Unlike
mice, rats exposed via inhalation did not exhibit DNA SSBs in liver and lung cell homogenates
or hepatocytes at 2,000 ppm or higher (Graves et al.. 1995; Graves et al.. 1994b). Similar to
results for mice, methylene chloride did not induce unscheduled DNA synthesis (UDS) in rat
hepatocytes after inhalation (Trueman and Ashbv. 1987). An intraperitoneal UDS study in rats
was also negative (Mirsalis et al.. 1989). Also similar to the results in mice, rats exposed to
methylene chloride at a single 5 mg/kg intraperitoneal dose exhibited no DNA adducts in liver or
kidney cells (Watanabe et al... 2007). Hamsters exposed to 4,000 ppm methylene chloride via
inhalation for 3 days did not exhibit DNA-protein cross links in liver or lung cells (Casanova et
al.. 1996).
In vitro testing in human cells and cell lines showed that methylene chloride induced micronuclei
(Doherty et al.. 1996) and sister-chromatid exchange (Olvera-Bello et al.. 2010) and exhibited a
weak trend in DNA damage based on the comet assay (Landi et al.. 2003). Methylene chloride
did not induce DNA SSBs (Graves et al.. 1995) or DNA-protein cross-links (Casanova et al..
1997) in human cells.
Page 283 of 753

-------
In vitro studies are also available for other mammalian tissues. Both mouse and rat hepatocytes
showed DNA damage when incubated with methylene chloride in vitro (Graves et ai. 1994b).
and DNA-protein cross-links were observed in mouse (but not rat) hepatocytes (Casanova et at..
1997). In mouse club lung cells tested in vitro, DNA damage was induced by methylene chloride
(Graves et at.. 1995). In vitro testing of hamster cells for forward mutations, sister chromatid
exchanges and DNA damage after methylene chloride exposure generally showed negative
results when testing was conducted without the addition of GST activity from mice (Graves et
at... 1995; Thilagar and Kumaroo. 1983; Jon sen et at.. 1981). When GST activity was added in
testing of hamster cells, positive results were seen for hprt mutation (Graves et at.. 1996; Graves
and Green. 1996). DNA damage (Hu et at.. 2006; Graves and Green. 1996). and DNA-protein
cross-links (Graves and Green. 1996; Graves et at... 1994b).
Both forward and reverse mutagenicity testing of methylene chloride in bacteria (S. typhimurium
and E.coli) has yielded positive results both with and without exogenous metabolic activation,
generally in strains such as TA 100 and TA98 that have higher GST activity (Demarini et at..
1997; Pegram et at.. 1997; Graves et al.. 1994a; Roldan landPuevo. 1993; Thier et at...
1993; Pitt on et al.. 1992; Zeig i ! i 'on. 1983; Jon gen et al.. 1982; Jon gen et al.. 1978).
As an example of mutations associated with GSTT1 activity, Demarini et al. (1997) found that in
Salmonella, methylene chloride was approximately 10 times more mutagenic in the presence of
GSTT1 than in the absence of GSTT1. Furthermore, all methylene chloride-induced mutations
induced G to A base substitutions in the presence of GSTT1, compared with only 15% G to A
substitutions in the absence of GSTT1, showing the difference in mutation signature with
GSTT1.
Other Mechanistic Data
Available data are not adequate to consider other modes of action for risk evaluation. Kari et al.
(1993) (cited in U.S. EPA (2011)) found no evidence of cytotoxicity or proliferative non-
neoplastic lesions preceding tumors in a series of stop-exposure studies focused on the liver and
lung. Also, sustained cell proliferation was not observed in livers of female mice exposed to
methylene chloride (Foley et al.. 1993) (cited in U.S. EPA (2011)). There is no evidence of
histologic changes or increased cell proliferation in lung tissue of female B6C3F1 mice exposed
to methylene chloride for up to 26 weeks (Kan.no et al.. 1993). Although acute exposure
produced cell proliferation in bronchiolar epithelium, it was not sustained with longer exposure;
proliferation may have been a response to vacuolization of club cells and may have involved a
CYP metabolite (Foster et at.. 1994). Some cell proliferation has been observed at higher
concentrations (5250-14000 mg/m3) in lungs of mice but not at lower concentrations
(1750 mg/m3 and below) after acute exposure; data, however, are not available after longer-term
exposure (Casanova et at... 1996). Finally, Aiso et al. (2014a) identified significant increases in
hyperplasia in terminal bronchioles in mice only at 14,000 mg/m3 whereas lung tumors were
significantly increased at > 3510 mg/m3.
Andersen et al. (2017) identified changes in gene expression in mice exposed to methylene
chloride, with marked changes occurring in several genes associated with circadian clocks.
Page 284 of 753

-------
Results indicate that liver and lung tumors from methylene chloride exposure appear to be
related to core changes in circadian processes in liver and lung tissue. Andersen et al. (2017) also
link circadian rhythms to metabolism showing different patterns in lung versus liver tissue. The
common circadian clock effects are for genes that code for regulatory proteins. The authors also
identified decreased tissue oxygenation from elevated COHb and the altered association of
reduced oxygenation to both circadian cycle proteins and tissue metabolism as the likely mode of
action for tissue responses to methylene chloride, but they note that this conclusion is tentative.
Data were not identified suggesting a receptor-mediated mode (e.g., peroxisome proliferation
resulting from PPAR-a activation; enzyme induction by constitutive androstane receptor (CAR),
pregnane X receptor (PXR), or aryl hydrocarbon receptor (AhR) activation).
3.2.4 Weight of Scientific Evidence
The following sections describe the weight of the scientific evidence for both non-cancer and
cancer hazard endpoints. Factors considered in weighing the scientific evidence included
consistency ansd coherence among human and animal studies, quality of the studies (such as
whether studies exhibited design flaws that made them unacceptable) and biological plausibility.
Relevance of data was considered primarily during the screening process but may also have been
considered when weighing the evidence.
3.2.4.1 Non-Cancer Hazards
The following sections consider and describe the weight of the scientific evidence of health
hazard domains discussed in Section 3.2.3.1. These domains include toxicity from acute/short-
term exposure; liver effects; nervous system effects; immune system effects; reproductive and
developmental effects; and irritation/burns.
3.2.4.1.1 Toxicity from Acute/Short-Term Exposure
Medium confidence human experimental studies of objective measures indicate that CNS
depression is a sensitive and common effect after acute exposure (e.g., (Putz et al.. 1979;
Winneke. 1974; Stewart et al.. 1972)). Although Stewart et al. (1972) also evaluated subjective
symptoms, these results were given a low confidence rating due to lack of blinding. Information
from case reports of accidental or large exposures supports this conclusion (Nrc. 2008). Data
suggest that increased COHb levels result in CNS depression (Putz et al.. 1979) but also support
an independent and possible additive effect of methylene chloride with COHb levels based on a
weaker (or no) effect on the nervous system from exogenous CO compared with methylene
chloride administration (Putz et al.. 1979; Winneke. 1974). Although COHb can continue to rise
after exposure has ceased and thus COHb may still be relevant at longer time points, both Putz et
al. (1979) and Winneke (1974) were conducted for 3.8 or 4 hours, and EPA considers Putz et al.
(J979) to still be relevant for an 8-hour duration.
The nervous system effects are supported by inhalation toxicity data in animals showing CNS
depression with decreased motor activity, changes in responses to sensory stimuli and some
impairment of memory (	). Data from oral animal studies also identified nervous
system effects that include sensorimotor and neuromuscular changes after acute and short-term
exposure as well as excitability, autonomic effects, decreased activity and convulsions (one rat)
after short-term exposure (Moseretal.. 1995; General Electric Co. 1976a).
Page 285 of 753

-------
Cardiotoxicity has been rarely reported as the sole cause of deaths or poisonings from methylene
chloride and is not identified as the most sensitive effect in available evidence (Nac/Aegl. 2008b;
DR. 2000).20 However, during exercise, individuals with cardiac disease have been
identified as experiencing angina more quickly after CO exposure and resulting increases in
COHb (Nac/Aegl. 2008b). Based on this evidence and the limited data that does suggest some
association between methylene chloride and cardiac endpoints, EPA considers that increased
COHb levels resulting from inhalation exposure to methylene chloride may also result in adverse
effects in individuals with cardiac disease, a sensitive subpopulation. Data are available from
human toxicokinetic studies that link increased methylene chloride exposure to increased COHb
levels in blood; many of these studies (Andersen et at.. 1991; Divincenzo and Kaplan. 1981;
Peterson. 1978; Astrand et at.. 1975; J	) were used as the basis of the SMAC.
Although acute effects other than CNS effects have been reported in human and animal studies
(such as liver or lung effects), they are less often reported, based on inconclusive evidence or are
not as sensitive (e.g., reported in lethal or non-lethal case reports after exposure to high or
expected high methylene chloride concentrations) (Nac/Aegl. 2008b). Furthermore, although
NAC/AEGL (2008b) report effects in lungs, liver and kidneys after acute high exposures,
methylene chloride concentrations are most often highest in the brain after acute lethal
concentrations.
Liver and lung effects were seen in an acute inhalation study in rodents but at higher
concentrations and lung effects appeared to be transient (Shell Oil. 1986). Immunosuppressive
effects were observed in rats after acute exposure to 100 ppm, a lower air concentration than the
levels associated with CNS effects observed in human studies (Aranyi et at.. 1986). However,
immune effects were not considered for dose-response analysis because data are sparse and
inconclusive when considered along with the human data on immune system effects (see Section
3.2.3.1.3).
Overall, there is evidence to support adverse effects following acute methylene chloride
exposure that include nervous system effects and the potential for adverse cardiac-related effects
from increased COHb in people with underlying cardiac conditions or heart disease. Therefore,
effects resulting from acute exposure were carried forward for dose-response analysis.
3.2.4.1.2 Liver Effects
Most human epidemiological studies did not investigate non-cancer liver effects. Of the
identified studies that measured changes in liver enzymes, two found evidence of increased
serum bilirubin (General Electric Co. 1990; Ott et ai. 1983a). GE (1990) received a data quality
rating of medium.
Both inhalation and oral studies identified liver effects as sensitive non-cancer effect linked with
exposure to methylene chloride in animals. Vacuolization, necrosis, hemosiderosis and
hepatocellular degeneration have been identified in subchronic and chronic inhalation studies in
rats, mice, dogs and monkeys (Mennear et at.. 1988; Nitschke et at.. 1988a; NTP. 1986; Burek et
20 Tomenson (20.1.1). Lanes et al. (1.993) and Hearne and Pifer (1999) did not identify an increased risk of mortality from
cerebrovascular disease or ischemic disease in three cohorts of workers producing cellulose triacetate film/fiber. These studies
received data quality scores of medium (1.7), medium (1.8) and high (1.6), respectively.
Page 286 of 753

-------
at.. 1984; Haun et al. 1972; Haun et al.. 1971). A newer study (Also et at.. 2014a) identified
acidophilic and basophilic foci in rats but not mice after chronic inhalation exposure. An oral
study also identified altered liver foci (Serota et at.. 1986a). In both studies, liver foci were not
correlated with tumors, and thus, EPA considers them to be non-neoplastic. Studies received
high and medium data quality ratings.
Fatty liver, a more severe effect compared with vacuolization, was seen in rats and dogs (Haun et
at.. 1972; Haun et al.. 1971); oral studies also identified fatty liver in mice and rats (Serota et al..
1986a. b). Based on these fatty liver changes that can be considered a more severe effect and
progression from vacuolization, U.S. EPA (2.011) suggested that vacuolization should be
considered toxicologically adverse and not simply an adaptive change.
U.S. EPA (2011) noted that limited MOA studies are available for methylene chloride regarding
non-cancer liver effects. Information identified in the post-IRIS literature search is also limited
and does not offer significant insight into the MOA as it relates to non-cancer liver toxicity. A
specific MOA cannot be discerned from the changes in gene and protein expression measured in
several studies (Park and Lee. 2014; Kim et al.. 2013; Kim et al.. 2010). Although Chen (2013)
identified increased biliary excretion of GSH and increased bile secretion, again, it is not clear
how these changes inform the vacuolization, necrosis and other apical effects observed in animal
studies. Dzut-Caaroat et al. (2013) identified lipid peroxidation and oxidation of proteins in livers
of fish exposed to methylene chloride. Lipid peroxidation affects lipids directly but can also
produce electrophiles and free radicals that can react with DNA and proteins (Greens. 2008).
Overall, based on limited human evidence and evidence in multiple animal species from highly
rated studies, there is evidence to support non-cancer liver effects following methylene chloride
exposure. Therefore, this hazard was carried forward for dose-response analysis.
3.2.4.1.3 Immune System Effects
Overall, human, animal and mechanistic studies provide suggestive evidence of methylene
chloride's association with immune-related outcomes. Appendix M presents a detailed evidence
integration analysis of immune system effects.
Among the epidemiological studies, which received medium to high confidence ratings, three
studies suggested an association between methylene chloride and immune-related, or possible
immune-related, outcomes. Chaigne, et al. (2015) identified high-magnitude ORs spanning 9-11
(95% CI: 2.38-51.8) for methylene chloride's association with Sjogren's syndrome, an
autoimmune disorder. Radican et al. (2008) also identified a high magnitude HR of 9.21 (95%
CI: 1.03-82.7) for increased mortality from bronchitis, a less specific and not clearly immune-
related endpoint. Finally, hoechst celanese cc 92) found some elevation of mortality from
flu and pneumonia associated with methylene chloride exposure (SMR 1.25 for males and 4.36
for females) that was not statistically significant. Despite these suggested associations, all studies
had limited information on methylene chloride exposure, none controlled for other chemicals and
Radican et al. (2008) investigated a non-specific outcome and used exposed and comparison
populations with very different socioeconomic status. Given these limitations, the
epidemiological studies were not used to estimate a quantitative dose-response relationship.
Page 287 of 753

-------
Two additional epidemiological studies found no or decreased associations with methylene
chloride. Hearne and Pifer (1999) observed decreased mortality rates from infection or and Lanes
et al. (1993) found no increase in mortality from non-malignant respiratory disease. These two
studies used general population death rates and thus, the healthy worker effect21 may have
resulted in attenuation of any possible association with methylene chloride.
Although one animal study is suggestive for immune-related effects, the body of scientific
evidence from animals is limited. Aranyi et al. (1986). a medium quality study, investigated and
identified increased mortality due to infection and impaired bacterial clearance and bactericidal
activity. Warbrick et al. (2.003). a high-quality study, found no differences in IgM antibody
responses to sheep red blood cells among methylene chloride-exposed rats compared with
controls. Warbrick et al. (2003) reported decreased spleen weights in female rats. NTP (1986)
identified changes in the spleen (fibrosis and follicular atrophy of the spleen in rats and mice,
respectively) but other chronic and subchronic inhalation studies didn't identify histopathological
changes in spleens, lymph nodes, or thymi of rats. In addition, evidence is not available from
other animal studies regarding changes in immune cell populations. Although there is some
evidence for immunosuppression from Aranyi et al. (1986). EPA considers the database to be
limited, with a lack of support from most other animal studies.
Data on modes of action are very limited. Methylene chloride may result in anti-inflammatory
effects (as evidenced by changes in specific cytokines demonstrated by Kubulus et al. (2008)).
but it has also been associated with generation of ROS in mononuclear cells (Uraga-Tovar et al..
2014). It is possible that multiple mechanisms may be at work, but with such limited data, EPA
cannot conclude that methylene chloride has a specific MOA.
Overall there is some evidence to support immune system effects following methylene chloride
exposure, but data are sparse with an apparent lack of consistency. Therefore, this hazard was not
carried forward for dose-response analysis.
3.2.4.1.4 Nervous System Effects
CNS Depression and Spontaneous Activity
Based on the availability of multiple studies in humans and animals, CNS depression is a
primary neurotoxic effect associated with methylene chloride. Mechanism studies are not
definitive for this endpoint. Increased dopamine in the medulla and increased GABA and
glutamate in the cerebellum by methylene chloride may be part of the MOA for these effects
(Kanada et al... 1994); however, this study did not measure functional changes so firm
conclusions regarding the MOA for CNS depression and motor changes are not possible. Studies
have not been conducted to evaluate the neurochemical basis for changes in spontaneous activity
for methylene chloride (Bale et al.. 2011).
21 One aspect of the healthy worker effect is related to the fact that morbidity and mortality rates are generally lower in workers
than the general population (Li and Sung, 1.999). since the latter includes individuals who are unable to work due to illness.
Page 288 of 753

-------
Lash et al. (1991) identified decreased attention and complex reaction tasks among retired
aircraft maintenance workers (data quality rating of medium). Although this study suggests a
possible chronic nervous system effect, the effect was observed in only one study and was not
statistically significant and so it is difficult to make conclusions from this study.
Although the MOA is not clearly delineated, multiple human and animal studies indicate that
methylene chloride is associated with nervous system effects. Based on this evidence, EPA
determined that methylene chloride should be brought forward for dose-response modeling.
Specifically, CNS effects are brought forward for dose-response modeling of effects from
acute/short-term exposure.
Developmental Neurotoxicity
Five epidemiological studies have evaluated the association between measured and modeled
outdoor ambient air concentration estimates of many air pollutants (often starting with the 33-37
HAPs, although Roberts et al. (2013) investigated many more pollutants) and ASD for regions
across the U.S. (Talbott et al.. /on Ehrenstein et al... 2014; Roberts et al. 2013;
Kalkbrenner et al... 2010; Windham et al.. 2006).
EPA has not advanced the ASD hazard to dose-response for several reasons. First, there are
uncertainties in the modeled estimates of air concentrations from NATA. Specifically, the NATA
data are annual average concentrations from the year of the pregnancy or within a few years of
the pregnancy. However, an etiologically relevant time period of exposure for ASD is thought to
be the perinatal period (Pelch et al.. 2019; Kalkbrenner et al.. 2010; Rice and Barone. 2000) and
the lack of temporal specificity of the NATA data, especially when considering averages over
multiple years, is a potential limitation. In addition, the estimates from these studies do not
consider possible contribution of any unmeasured exposure by workers or indoor home
exposures. Several of the current studies address multi-pollutant exposures within the same
regression models but other studies only identify correlations among chemicals that are also
independently associated with ASD. Therefore, certain methylene chloride odds ratios may be
overstated in the studies that did not include these correlated chemicals in the same regression
equation.
Animal studies identified effects on habituation, an early form of learning and memory,
(Bomschein et al.. 1980) and effects in other learning tests (Alexeeff and Kilgore. 1983) at high
single concentrations following developmental exposure. However, these studies used only
single high concentrations and were not considered appropriate to use in calculating risks.
Despite methodological limitations in the human studies and concentration limitations in the
animal studies, the available information provides evidence of an association between methylene
chloride exposure and developmental neurological effects.
3.2.4.1.5 Reproductive and Developmental Effects
Epidemiological studies sometimes identify reproductive/developmental effects, including oral
cleft defects in mothers older than 35 years and heart defects in mothers of all ages (Brender et
al.. 2014) and spontaneous abortions (Taskinen et al.. 1986). However, these studies didn't
directly consider co-exposures within the same model as methylene chloride. Brender et al.
Page 289 of 753

-------
(2.014) ran independent analyses with other chemicals, which showed associations in mothers of
all ages or showed more positive associations. Taskinen et al. (1986) found that other chemicals
resulted in similar magnitude of spontaneous abortions and furthermore, received a low data
quality rating.
Some animal studies (Alexeeff and Kilgore. 1983; Bornschein et al.. 1980; Hardin and Manson.
1980; Schwetz et al.. 1975) identified effects that included developmental neurotoxicity but these
were observed at higher concentrations (1,250, 4,500 or 47,000 ppm). Although Raje et al (1988)
identified reduced fertility at 144 ppm, results failed to reach statistical significance in two of
three statistical tests. Three oral reproductive/ developmental studies (Narotsky and Kavlock.
1995; Nitschke et al.. 1988b; General Electric Company. 1976) didn't identify reproductive and
developmental toxicity. Also, multiple animal studies used only a single concentration.
Some studies identify reproductive and developmental effects, including developmental
neurotoxicity. Also, as noted in section 3.2.4.1.4, adults are sensitive to neurotoxicity and
transfer of methylene chloride to the placenta is possible. Epidemiological studies lacked
controls for co-exposures, animal studies observed effects mostly at higher methylene chloride
concentrations in animals and EPA identified no relevant mechanistic information. Thus, EPA
did not carry reproductive/developmental effects forward for dose-response.
3.2.4.1.6 Irritation/Burns
Data from case reports, an occupational study and animal data indicate that irritation is possible.
Based on direct contact from accidents or suicide attempts, methylene chloride has been shown
to result in burns to the eyes and skin (Fisk and Whittak	, 1DR. 2000; Hall and
Ruroack. 1990). Gastrointestinal tract irritation is also expected, and was suggested in a suicide
case, assuming methylene chloride was the causative agent (Hushes and Tracev. 1993). Irritation
has been identified after inhalation of methylene chloride vapor in some cases (Anundi et al..
1993) but not others (Stewart et al. 1972).
Documentation that supports the OSHA (1997a) standard notes that methylene chloride may lead
to a burning sensation if it remains on skin but notes that after short-term exposure, it is not
corrosive. OSHA (1997a) states that individuals should avoid skin contact based on its irritating
properties.
Based on data from humans and animals, there is evidence that methylene chloride is associated
with irritation and possible burning of skin, eyes and mucous membranes. A full elucidation of
the circumstances leading to irritation is not available because studies in humans are limited and
it is not easy to quantify these effects. For these reasons, irritation and burns will not be carried
forward for dose-response modeling but are qualitatively discussed in the risk characterization.
3.2.4.2 Genotoxicity and Carcinogenicity
There is sufficient evidence of methylene chloride carcinogenicity from animal studies.
Methylene chloride produced tumors at multiple sites, in males and females, in rats and mice, by
oral and inhalation exposure, and in multiple studies. The most prominent findings were
significant increases in liver (hepatocellular adenoma/carcinoma) and lung (bronchoalveolar
adenoma/carcinoma) tumor incidences in male and female B6C3F1 and Cij:BDFl mice by
Page 290 of 753

-------
inhalation exposure in two separate bioassays (Also et al. 2014a; NTP. 1986). liver tumors in
male B6C3F1 mice exposed via drinking water (Serota et al.. 1986b; Hazleton Laboratories.
1983). and mammary gland tumors (adenoma/fibroadenoma) in male and female F344/N and
F344/DuCrj rats exposed by inhalation in two separate bioassays (Also et al.. 2014a; NTP.
1986). Other findings potentially related to treatment included increases in liver tumors in male
rats with inhalation exposure (Also et al.. 2.014a) and female rats with drinking water exposure
(Serota et al.. 1986a; Hazleton Laboratories. 1983); hemangiomas/hemangiosarcomas in male
and female mice by inhalation exposure (Also et al.. 2014a); mononuclear cell leukemia in
female rats by inhalation exposure (Also et al.. 2014a; NTP. 1986); mesotheliomas,
subcutaneous fibromas/fibrosarcomas, and salivary gland sarcomas in male rats by inhalation
exposure (Aiso et al.. 2014a; NTP. 1986; Burek et al.. 1984); and brain (glial cell) tumors in
male and female rats by inhalation exposure (Nitschke et al.. 1988a).
Although a number of relevant studies are available, findings were inconclusive for cancers of
the liver, lung, breast, brain and CNS, and most hematopoietic cancer types, due to weaknesses
of the individual studies and inconsistent results across studies. For these endpoints, the
epidemiological studies provide only limited support for a relationship between methylene
chloride exposure and tumor development.
While findings were also inconclusive for hematopoietic cancers (leukemia, multiple myeloma,
Hodgkin lymphoma), including NHL, ORs for B-cell subtypes of NHL were consistently
increased across all three case-control studies that evaluated this tumor type (Barry et al.. 2011;
Seidler et al.. 2007; Miligi et al.. 2006). and ranged from 1.6 to 3.2 with marginal statistical
significance identified for two of the studies. Despite this greater consistency, the studies
evaluating the B-cell subtypes did not adjust for other chemical co-exposures, and there was
correlation among exposures for several chemicals. Furthermore, several chemicals showed
some association with B-cell NHL. Thus, firm conclusions regarding the specific association
between methylene chloride and the outcomes cannot be made.
Epidemiological studies inherently have limitations that decrease their ability to identify
associations between outcomes and exposures. Although not a complete or exhaustive list,
limitations regarding the epidemiological studies considered here and their ability to detect risks
associated with methylene chloride are described here:
1) It is preferred that cohort studies use comparison (i.e. non-exposed) groups drawn
from the same source population that are similar to the exposed groups to reduce the
potential for selection bias. Most of the occupational cohort studies that evaluated
risks by exposed workers to methylene chloride (Tomenson. 2011; Hearne and Pifer.
1999; Gibbs et al.. 1996; Lanes et al.. 1993) used SMRs or standard incidence rates
(SIRs), which use rates from the general population - whether working or not - as
comparison groups. This may lead to the healthy worker effect, which results in
selection bias and other types of biases, since the characteristics of the general
population are likely to differ from the population of workers being evaluated
(REFS). Morbidity and mortality rates are generally lower in workers than the general
population (Li and Sung. 1999). since the latter includes individuals who are unable
to work due to illness. According to Li and Sung (1999). some authors suggest that
Page 291 of 753

-------
the effect of these dissimilar groups (workers vs. general population) may be
somewhat mitigated when considering mortality from cancer as an endpoint and for
studies that included both active workers and retired individuals (Hearne and Pifer.
1999). The healthy worker survivor effect is another type of healthy worker effect
that occurs when those who remain employed in the workforce are healthier than
those who leave employment. This type of bias predominately serves to attenuate
(bias towards the null value of no association) effect estimates related to the
exposure(s) of interest. These types of comparisons can lead to other sources of bias
beyond selection bias and may result in bias that is harder to gauge regarding
direction and impact. It is likely that the effects of methylene chloride in several of
these studies could be attenuated, such as in cohorts that use general population
comparison groups or were subject to the healthy worker survivor effect.
a.	Ability to classify individuals by degree of exposure information was limited. For
example, work histories were available for only 37% of the Lanes et al. (1993)
cohort, and were not specific for 30% of the Tomenson et al. ( ) cohort. One
study characterized methylene chloride exposure simply as yes/no (Radican et al..
2008). If exposure is misclassified, the results may be under or overpredicted. If
misclassification is random, it is likely to underestimate effects, but if it is not
random, effects may be under- or over-predicted (Hennekens and Buring. 1987).
b.	For lung cancer studies, smoking restrictions at work (Tomenson. ; hoechst
celanese corp. 1992.) limits the ability to interpret the inverse association because of
the potential for higher smoking rates in the general population. Lack of
information/adjustment regarding smoking (Lanes et al.. 1993) also limits the ability
to interpret results. Some of these results may also be compounded by the
aforementioned healthy worker effect.
c.	Low numbers of deaths or cases in several studies decrease study sensitivity making
it difficult to detect an effect or interpret results. Examples include Hearne and Pifer
(1999). Tomenson (2011). Radican (2008) and Christensen et al. ( ).
Some effects attributed to methylene chloride in epidemiological studies might instead be due to
confounding. For example, if epidemiological studies did not control for exposures or report
exposure information for other chemicals that are both positively associated with methylene
chloride and cancer, adverse associations with methylene chloride may be overstated. For
example, Miligi et al. (2006). Barry et al. (2011) and Seidler et al. (2007) identified some
association between methylene chloride and B cell NHL but did not control for other chemical
exposures. However, the only occupational epidemiological study to examine the impact of
solvent co-exposure showed that multi-chemical adjustment only slightly changed the ORs
(Miligi et al.. 2006).
One set of data suggesting a cancer MOA are the multiple studies indicating mutagenicity
associated with methylene chloride metabolites of the GST metabolic pathway catalyzed by the
GSTT1 isoenzyme (U.S. EPA. 2011). There are numerous genotoxicity tests showing positive
results for methylene chloride, including assays for mutagenicity in bacteria and mutagenicity,
Page 292 of 753

-------
DNA damage, and clastogenicity in mammalian tissues in vitro and in vivo (IARC. 2016; U.S.
ID-
The most strongly positive results in mammalian tissues in vivo and in vitro were found in
mouse lung and liver, tissues with the greatest rates of GST metabolism and the highest
susceptibility to methylene chloride-induced tumors. To further strengthen the case for the role
of GST-mediated metabolism, studies have demonstrated increases in damage with the addition
of GSTT1 to the test system and decreases in damage by addition of a GSH depletory. The
GSTT1 metabolic pathway has been measured in human tissues with activities that are generally
lower than rodents. In addition, human cells have exhibited genotoxicity without exogenous
addition of GSTT1 (U.S. EPA. 20111
When comparing metabolism of methylene chloride by the GST pathway in liver and lung
tissues among species, mice are more active than rats, humans and hamsters (	11).
Similarly, Thier et al. (1998) cited by U.S. EPA (2011) found species' specific liver GSTT1
isozyme activity after methylene chloride exposure to be ordered as follows (from highest to
lowest): mice, rats, human high and low conjugators, hamsters and human non-conjugators.
Thier et al. (1998) cited by U.S. EPA (2011) also reported that high and low human conjugators
exhibited GSTT1 activities in erythrocytes approximately 11 and 16 times higher, respectively,
than the human liver activities of high and low conjugators. Furthermore, the human high
conjugator GSTT1 activity in erythrocytes was the same as male mouse liver activity and 61% of
the female mouse liver activity. Increased GSTT1 activity in some human tissues may be partly
responsible for the observed associations between increased methylene chloride exposure and
cancer incidence in certain epidemiological studies.
Based on the evidence, EPA believes that the cancer results in animal studies are relevant to
humans. Reasons include the demonstration of mutagenicity in human cells without exogenous
GSTT1 and detected GSTT1 activity in human cells, some of which is comparable to GSTT1
activity in mice.
Other possible MO As are either not well established or have limited or no support. Andersen et
al- (2017) identified the altered association of reduced oxygenation to both circadian cycle
proteins and tissue metabolism as the likely MOA for tissue responses to methylene chloride.
Changes in circadian rhythm have been associated with cancer, and some research also links
hypoxia to changes in the circadian clock. IARC (2019) assigned night shift work as Group 2A,
probably carcinogenic to humans. IARC (2019) also suggested that the mechanistic evidence
included enhanced inflammation in rats; increased cell proliferation in transplanted tumors
associated with light-dark schedule changes; and immune suppression in nocturnal rats, mice and
Siberian hamsters. Altered tumor glucose metabolism was observed in female nude rats,
consistent with the Warburg effect (glucose fermentation in cancer cells) (tare. 2019). In addition
to the link between changes in the circadian clock and cancer, hypoxia has been shown to result
in some changes in the circadian clock (Andersen et al.. 2017).
However, certain mechanistic steps identified by IARC (2019) have not been established for
methylene chloride. In particular, enhanced cell proliferation was either not observed in livers of
Page 293 of 753

-------
mice after 78 weeks (Foley et at.. 1993) as cited in U.S. EPA (: ), or proliferation from acute
and short-term exposure was not sustained after longer (83-93 days) exposure (Casanova et at..
1996; Foster et at.. 1992.) as cited in U.S. EPA (2011). In addition, although methylene chloride
has been associated with immunosuppression (Aranyi et at.. 1986). EPA has concluded that the
evidence is limited. Furthermore, EPA did not identify an established adverse outcome pathway
(AOP) describing the molecular initiating and key events for hypoxia leading to changes in the
circadian clock and then subsequently to cancer.
U.S. EPA (2011) also evaluated sustained cell proliferation as an alternative MOA for methylene
chloride-induced lung and liver cancer. Enhanced cell proliferation was not observed in the liver
of female B6C3F1 mice exposed to 2000 ppm methylene chloride for up to 78 weeks (Foley et
at... 1993) as cited in U.S. EPA (2011). Furthermore, acute and short-term inhalation studies
showed enhanced cell proliferation in the lung; however, this effect was not sustained for longer
exposure durations (83-93 days of exposure) (Casanova et at.. 1996; Foster et at.. 1992) as cited
in U.S. EPA (2011). Also, data were not identified suggesting additional MOAs (e.g.,
peroxisome proliferation resulting from PPAR-a activation).
Although Andersen et al. (2017) provides an interesting hypothesis, EPA believes that the
evidence for the MOA and specific information for methylene chloride are lacking. Furthermore,
based on the identified additional biochemical and mechanistic data, EPA doesn't expect
sustained cell proliferation to be important in the development of liver and lung tumors and no
other receptor-mediated mechanistic information was identified. Therefore, U.S. EPA (2005a)
indicates the need for a well-established MOA to consider deviating from the default methods of
linear low-dose extrapolation.
In accordance with U.S. EPA (2005a) Guidelines for Carcinogen Risk Assessment, methylene
chloride is considered "likely to be carcinogenic to humans" based on sufficient evidence in
animals, limited supporting evidence in humans, and mechanistic data showing a mutagenic
MOA relevant to humans. Therefore, this hazard was carried forward for dose-response analysis.
3.2.5 Dose-Response Assessment
3,2.5.1 Selection of Studies for Dose-Response Assessment
EPA evaluated data from studies described in Sections 3.2.3 and 3.2.4 to characterize the dose-
response relationships of methylene chloride and selected studies and endpoints to quantify risks
for specific exposure scenarios. The selected studies had adequate information to select PODs.
3.2.5.1.1 Toxicity from Acute/Short-Term Exposure
Based on the weight of scientific evidence evaluation, one health effect domain (CNS
depression) was selected for dose-response analysis for effects from acute/short-term exposure.
Information from human studies (controlled experiments) are available for this endpoint.
CNS Depression
As discussed in Section 3.2.3.1.1, several controlled experiments in humans are available that
support the relationship between methylene chloride exposure and CNS effects. Although data
Page 294 of 753

-------
quality evaluation criteria are not available for the types of human studies considered, EPA
qualitatively evaluated studies used as the basis for the American Conference of Government
Industrial Hygienists (ACGIH) Threshold Limit Value (TLV)-TWA, California REL, SMAC,
and other studies identified in backwards searching of these documents. Data are also available
from animal studies to support this health effect domain during acute exposure, but the human
studies are considered adequate and are preferable to animal studies.
A primary consideration for choosing studies for dose-response assessment includes use of
objective tests (such as visual evoked responses) that measure CNS effects, and not simply
subjective reports of symptoms, especially when it is not known whether the investigator and
participants are blinded to the use of methylene chloride vs. control. Another consideration is
appropriate generation of methylene chloride air concentrations. Finally, EPA determined that
the changes in CNS effects are likely to be related not only to hypoxia from increased COHb
levels but also from increased levels of methylene chloride concentrations in the brain; therefore,
EPA placed greater importance on studies that identified effects from direct methylene chloride
exposure, not effects modeled from COHb levels. Although COHb can continue to rise after
exposure has ceased and thus COHb may still be relevant at longer time points, both Putz et al.
( 1) and Winn eke (1974) were conducted for 3.8 or 4 hrs and identified greater effects from
methylene chloride compared to CO (and Winneke (1974) did not identify effects from CO).
Thus, EPA considers direct CNS effects from methylene chloride to still be relevant for an 8-hr
duration.
Based on these considerations, EPA chose Putz et al. (1979) to estimate risks from acute/short-
term exposure. This study identified changes in visual peripheral response after 1.5 hrs (within a
4-hr exposure) in a dual complex task, adequately generated methylene chloride exposures and
used a double-blind procedure. The study received a medium confidence rating. Although
Winneke (1974) also identified similar effects from methylene chloride intake, the study did not
test concentrations lower than 300 ppm. Because Putz et al. (1979) identified effects at a
concentration not evaluated in other similar studies (195 ppm) and because CNS effects are
critical effects that lead to more severe effects at higher concentrations and longer exposure
durations, EPA chose Putz et al.(1979) for dose-response modeling for this endpoint.
3.2.5.1.2 Toxicity from Chronic Exposure
Non-Cancer
Hepatic effects are the primary dose-dependent non-cancer effects observed in animals after
chronic and subchronic exposure to methylene chloride. Although a few other sensitive effects
are observed for other health domains (e.g., some persistent nervous system effects in humans
observed by Lash et al. (1991). decreased fertility identified by Raje et al. (1988)). liver effects
are more consistently observed. The hazard identification and weight of evidence sections
(Section 1.5 and 3.2.1) both describe the evidence in more detail for each of these health
domains.
EPA is relying on the dose-response modeling results presented in U.S. EPA (2011) from
Nitschke (1988a) for rats. This study is the most suited to dose-response modeling because it is
the chronic study with the lowest exposure concentrations and was rated high for data quality.
Page 295 of 753

-------
As a comparison, EPA also considered results from the recent study by Aiso et al. (2014a) in
rats. However, the concentrations used in Aiso et al. (2014a) are higher (0, 3500, 7000 and
14,000 mg/m3) than the concentrations in the Nitschke et al. (1988a) study (0, 180, 700 and 1800
mg/m3).
The effects used in the dose-response modeling from both the Nitschke (1988a) and Aiso et al.
(2014a) studies are included in Table 3-15.
Page 296 of 753

-------
Table 3-15. Candidate Non-Cancer Liver Effects for Dose-Response Modeling
T;ire(
Orgsin/
System
Sluclj
Tj pe
Species/Sir;iin
/So\
(Number/
group)
Kxposmv
Runic
Doses/
('uncoil Initio n
Duration
NO A HI./
1.OA l-'.l.
reported In
iiulhors
NOAII./
1.OA l-'.l.
(inii/inJ or
m$*/kg-(lsi>)

-------
Cancer
The epidemiological studies generally provide only limited support for the relationship between
methylene chloride exposure and tumor development. Therefore, EPA relied on inhalation rodent
cancer bioassays to model the dose-response relationship. EPA modeled both the tumor response
data from NTP (1986) and data from a recent publication (Also et al.. 2014a).
EPA modeled the same tumor response data from NTP (1986) chosen for the inhalation unit risk
(IUR) as was modeled by U.S. EPA ( _), (i.e., liver, lung and mammary gland tumors). EPA
also included modeling with the full set of dichotomous models available in benchmark dose
software (BMDS) to evaluate the sensitivity of the model output to the model choice.
EPA also modeled dose-response data for several tumor types from a study published subsequent
to the IRIS assessment (Also et al.. 2014a). The tumors modeled included those with positive
trend tests, significant pairwise differences from controls, the most sensitive tumors as well as
the clearest dose-response data. EPA modeled lung and liver tumors in male and female mice. In
rats, EPA modeled mammary and subcutis tumors. Although EPA could have included tumor
types that had positive trend without statistically significant pairwise comparisons (similar to the
evaluation by U.S. EPA (2011)). the excluded tumor types exhibited lower incidences and the
dose-response relationships were generally unclear upon visual inspection. EPA provides more
information on why certain tumor types were not modeled in Appendix B of the supplemental
fil q Methylene Chloride Benchmark Dose and PBPK Modeling Report (EPA. 2019h).
NTP (1986) showed a clear dose-response with lung and liver cancer, and these data were chosen
for dose-response modeling (I _S MH 2011). Furthermore, the study received a high data
quality rating using the criteria specified in Application of Systematic Review in TSCA Risk
Evaluations (U.S. EPA. 2018b). Of the inhalation studies and tumor types considered, these
tumors were most sensitive to methylene chloride exposure in mice, yielding responses of greater
magnitude and more positive association than most other tumor data, other than the mostly
benign mammary tumors results (see Section 3.2.3.2.2).
Table 3-16. Candidate Tumor Data for Dose-Response Modeling presents tumor results from the
NTP (1986) and Aiso et al. (2014a) studies that were considered to be candidates for dose-
response modeling.
Page 298 of 753

-------
Table 3-16. Candidate Tumor Data for Dose-Response Modeling
Rcl'crciicc
Sir;iin iind
Species
l'l\|)osiire
rou le
Sex
l'l\|)OMire le\els
Tumor |\pc
Si^nirieiinl
dose-reliiled
Ircnri
Si^nirieiinl
pnirwise
com piiri soir1
Mxposure lc\cl
\\iili si^niriciinl
inciviisc'
Diilii Qu;ili(\
r.\ iiiuiiiion
Hepatic Tumors
NTP (1.986)
B6C3F1 mouse
Inhalation
M
0, 2000,4000 ppm
Hepatocellular adenoma
or carcinoma
y
y
4000 ppm
High



F

Hepatocellular adenoma
or carcinoma
y
y
> 2000 ppm

Aiso et al.
("2014b")
BDF1 mouse
Inhalation
M
0, 1000,2000,
4000 ppm
Hepatocellular adenoma
or carcinoma
y
y
> 2000 ppm
High





Hepatic hemangioma
y
y
4000 ppm






Hepatic hemangioma or
hemangiosarcoma
y
-
-




F

Hepatocellular adenoma
or carcinoma
y
y
> 1000 ppm






Hepatic hemangioma
y
-
-






Hepatic hemangioma or
hemangiosarcoma
y
-
-

Lung Tumors
NTP ("19861
B6C3F1 mouse
Inhalation
M
0, 2000,4000 ppm
Bronchoalveolar adenoma
or carcinoma
y
y
> 2000 ppm
High



F

Bronchoalveolar adenoma
or carcinoma
y
y
> 2000 ppm

Aiso et al.
(2014b)
BDF1 mouse
Inhalation
M
0, 1000,2000,
4000 ppm
Bronchoalveolar adenoma
or carcinoma
y
y
> 1000 ppm
High



F

Bronchoalveolar adenoma
or carcinoma
y
y
> 2000 ppm

Page 299 of 753

-------
Reference
Sir;iin iiiul
Species
r.\|)(isuiv
ion (e
Sox
I'.xposiirc le\ els
Tumor l\pc
Si^niriciinl
(Insc-rchilcd
(lend
Si^niriciinl
p;iir\\isc
comparison'1
I'.xposiirc lc\cl
willi si^niriciinl
inciviisr1
Diilii Qii;ili(>
l'.\ ;ilu;ilion
Mammary Tumors
NTP ("19861
F344 rat
Inhalation
M
0, 1000,2000,
4000 ppm
Mammary or
subcutaneous tissue
adenoma, fibroadenoma,
or fibroma
y
y
4000 ppm
High



F

Mammary adenoma,
fibroadenoma, or
adenocarcinoma
y
y
> 2000 ppm

Aiso et al.
C2014b1
F344/DuCij
Inhalation
M
0, 1000,2000,
4000 ppm
Mammary gland
fibroadenoma
y
y
4000 ppm
High





Mammary gland
fibroadenoma or adenoma
y
y
4000 ppm






Mammary gland
fibroadenoma or adenoma
or adenocarcinoma
y
-





F

Mammary gland
fibroadenoma
y
-







Mammary gland
fibroadenoma or adenoma
y
-







Mammary gland
fibroadenoma or adenoma
or adenocarcinoma
y
-


Subcutaneous Tumors
Aiso et al.
("20141)1
F344/ DuCij
Inhalation
M
0, 1000,2000,
4000 ppm
Subcutaneous fibroma
y
y
> 2000 ppm
High



Subcutaneous fibroma or
fibrosarcoma
y
y
> 2000 ppm

aAs reported in the cited reference
Page 300 of 753

-------
3.2.5.2 Derivation of PODs and UFs for Benchmark Margins of Exposures (MOEs)
3.2.5.2.1 PODs for Acute/Short-term Inhalation Exposure
Workers and consumers can be exposed to a single acute exposure to methylene chloride under
various conditions of use via inhalation and dermal routes. EPA identified PODs for several
acute inhalation exposure durations based on both hazard and exposure considerations. A
duration of 8 hrs, a typical work shift, is used for occupational settings. For workers, EPA also
evaluated a 15-minute exposure, which matches the duration used to set the STEL. Furthermore,
some concentrations of methylene chloride in occupational settings are reported for 15 minutes
or similar durations.
A 1-hr value is used for consumer settings, which is similar to the length of time (1.5 hrs) after
which effects were observed by Putz et al. (1979).
Putz et al. (1979) is a well-conducted study of 12 volunteers that identified decreased visual
peripheral performance after 1.5 hr of exposure to 195 ppm (200 ppm nominal). Results of
EPA's qualitative data quality evaluation indicate that this study is of medium quality and unlike
other key studies that have been evaluated, Putz et al. (1979) conducted his study in a double-
blind manner. Because this study used a single concentration, it is not amenable to dose-response
modeling, so EPA used the LOAEC of 195 ppm. Both OSHA and ACGIH cited the nominal
value of 200 ppm as a LOAEC for CNS effects. ACGIH used this study with a safety factor of 4
to account for interindividual differences in sensitivity and use of a LOAEC rather than a
NOAEC as the basis of its 8-hr TLV-TWA of 50 ppm.
The Office of Environmental Health Hazard Assessment (OEHHA) from the state of California
uses Putz et al. (1979) as the basis of their REL. OEHHA (2.008a) used a simplified equation, Cn
x T = K with n = 2, to scale the LOAEC of 195 ppm (696 mg/m3) for 1.5 hrs to values of 240
ppm (840 mg/m3) and 80 ppm (290 mg/m3) for 1 and 8 hours, respectively. This equation is a
modification of Haber's rule, and n = 2 is based on an analysis by ten Berge et al. (1986). of
concentration times time for lethality data from 20 acute inhalation studies of various compounds
that resulted in an average value of 1.8 for n. OEHHA (2008a) used a total UF of 60 based on an
intraspecies UF of 10 to account for human variability and a LOAEL-to-NOAEL UF of 6
(Oehha. 2008a).
The NAC/AEGL has used CnxT = K when setting AEGLs and has also used n = 2 when no
exposure-versus-time data are available (NA.SEM (National Academies of Sciences. 2000).
Although there is uncertainty in using n=2 to extrapolate to longer time periods, ten Berge et al.
(1986) identified the value of n = 1.8 from LCso studies, which typically are 4 hours long. Thus,
it was considered appropriate to use this for an 8-hour period.
For methylene chloride, exposure-versus-time data are limited. Therefore, EPA considers the ten
Berge equation using n = 2 as a valid method to convert the 1.5 hour POD value from Putz et al.
(1979) to the 15-minute, 1 -hour and 8-hour PODs (see Table 3-17).
Page 301 of 753

-------
Although EPA considered using the PBPK model described by Bos et al. (2006). EPA believes
that there are enough uncertainties regarding the assumptions, validation and precision of the
model that don't warrant using it instead of the ten Berge equation. Although the model accounts
for P-450 saturation and a switch to conjugation catalyzed by GSTT1, P450 saturation occurs at
approximately 500 ppm, which is higher than the POD for the current evaluation. In addition,
although the model includes the distribution of GSTT1 in the population, EPA considered this
refinement less necessary when using human volunteers, especially at lower methylene chloride
concentrations. Furthermore, the parent compound has been shown to result in CNS effects that
are in excess of CO/COHb concentrations. However, Bos et al. (2006) acknowledge that there
are no adequate data on methylene chloride in rat or human brains and also assume that at longer
exposures, the more relevant endpoint is COHb only. OSHA, when considering a similar PBPK
model for acute effects for derivation of the 1997 PEL, had similar concerns about the lack of
experimental validation of the predicted brain MC concentrations (OSHA.., 1997a). In addition,
although EPA understands that the COHb concentrations may be maintained for several hours
after exposure ceases (and a primary reason to consider this type of PBPK model), this effect is
not as pronounced at lower concentrations. Finally, Bos et al. (2006) state that the model
overpredicts methylene chloride and COHb concentrations by up to 50%. Thus, although the
PBPK model has features that may be important for setting other limits set higher values, such as
AEGLs, EPA considers the ten Berge equation to be appropriate for the current risk evaluation.
Table 3-17. Conversion of Acute POPs for Different Exposure Durations
Kxposure
Duration for

l i s for
Benchmark MOK


Value
POD
ii.ii
Kml point
References
15-min
478 ppm
UFh= 10
7% J, visual
CNS data from Putz

(1706 mg/m3)
UFl = 3
peripheral
et al. (1979);
1-hr
240 ppm (840
mg/m3)
Total UF = 30
performance at
1.5 hrs
Conversion of
concentrations



among exposure
durations use ten
Berge et al. (1986)
equation Cn x T = K,
where n = 2
8-hr
80 ppm
(290 mg/m3)


a.	Margin of Exposure (MOE) = Non-cancer POD / Human exposure
b.	UFh= intraspecies uncertainty factor; UFL= LOAEL-to-NOAEL uncertainty factor
EPA applied a composite UF of 30 for the acute inhalation benchmark MOE, based on the
following considerations:
1)	Interspecies uncertainty/variability factor (UFa) of 1
Accounting for differences between animals and humans is not needed because the POD
is based on data from humans
2)	A default intraspecies uncertainty/variability factor (UFh) of 10
To account for variation in sensitivity within human populations due to limited
Page 302 of 753

-------
information regarding the degree to which human variability may impact the disposition
of or response to, methylene chloride.
a.	Some of the specific variabilities/uncertainties for methylene chloride that can lead to
greater risk and are accounted for with this UFh include toxicokinetic differences:
Fetuses
Fetuses are at higher risk for CO toxicity and resulting CNS effects because of higher CO
affinity for hemoglobin and slower CO elimination (Nrc. 2010). There are no studies
reporting effects on the unborn after a single acute exposure resulting in lower COHb
levels (Nrc. 2010; U.S. EPA. 20001
Workers, consumers engaged in vigorous activity
It has been shown that greater metabolism to CO occurs in individuals who are exercising
(Nac/Aegt. 2008b). This leads to increased COHb and subsequent effects that may
exacerbate the CNS effects. Workers or consumers who are engaged in more vigorous
activity would be expected to exhibit greater effects due to additional CNS effects of
increased COHb. In addition, exercise increases the rates of respiration and cardiac
output, both of which are important in increasing systemic uptake of VOCs such as
methylene chloride.
Individuals with higher CYP2E1 enzyme levels
Several other chemicals, including alcohol, can induce CYP 2E1 and lead to greater
metabolism that leads to increased CO and COHb levels. Thus, individuals who consume
large amounts of alcohol may be at greater risk.
Smokers
Smokers have higher levels of COHb and therefore, additional increases in COHb from
methylene chloride exposure may lead to increased CNS effects or increased angina in
individuals with heart disease.
b.	Some of the specific variabilities/uncertainties related to toxicodynamic differences
based on potentially susceptible subpopulations are as follows:
Individuals with heart disease/cardiac patients
At COHb levels of 2 or 4%, patients with coronary artery disease may experience a
reduced time until onset of angina (chest pain) during physical exertion ( Allied et at..
1991: Allred et at.. 1989a: Altred et at.. 1989b). Other studies have also confirmed a
reduced time to onset of exercise-induced chest pain at a COHb between 2.5 and 4.5
percent (Kleinman et at.. 1998: Kteinman et at.. 1989; Sheps et at.. 1987; Anderson et at..
1973; Aronow c	). The SMAC (Nrc. 1996) identified a NOAEC of 100 ppm for
a 3% COHb level and because decreased time to angina may occur at even lower levels,
this UF is considered important to account for this susceptible subpopulation. These
values are lower than the value from Putz et al. (1979) used for the acute endpoint; the
COHb level was measured as 5.1%.
Page 303 of 753

-------
c. Furthermore, additional differences among individuals that may result from either
toxicokinetic or toxicodynamic differences may be of concern:
Bystanders of different ages
Residential bystanders for consumer uses are expected to be indirectly exposed to
methylene chloride and may be of any age. For example, elderly individuals who may
have other health concerns (e.g., those related to nervous system effects) may be more
susceptible to the effects of methylene chloride from acute exposure.
3) A LOAEC-to-NOAEC uncertainty factor (UFl) of 3
This factor was applied to account for the lack of NOAEC in the critical study. A value of 3
rather than a more conservative value of 10 is applied because the effects observed by Putz
et al. (1979) after one and one-half hours are of a small magnitude (decreased 7% in one
measure - visual peripheral changes).
3.2.5.2.2 PODs for Chronic Inhalation Exposure
Chronic exposure was defined for occupational settings as exposure reflecting a 40-hour work
week. A set of dichotomous dose-response models that are consistent with a variety of
potentially underlying biological processes were applied to empirically model the dose-response
relationship in the range of the observed data. The models in EPA's BMDS were applied to
selected studies. Consistent with EPA's Benchmark Dose Technical Guidance Document (EPA.
2012a). the BMD and 95% lower confidence limit on the BMD (BMDL) were estimated using a
benchmark response (BMR) to represent a minimal, biologically significant level of change,
referred to as relative deviation (RD). In the absence of information regarding the level of change
that is considered biologically significant, a BMR of 10% extra risk (ER) for dichotomous data is
used to estimate the BMD and BMDL, and to facilitate a consistent basis of comparison across
endpoints and studies. The estimated BMDLs were used as PODs; the PODs are summarized in
Table 3-19 for non-cancer liver effects and in Table 3-20 includes information for cancer
endpoints. Details on derivation of the IUR for cancer and the non-cancer HEC are included in
Appendix I. More information and the full suite of models, model outputs and graphical results
for the model selected for each endpoint can be found in Supplemental File: Methylene Chloride
Benchmark Dose andPBPKModeling Report (EPA. 2019h).
Non-Cancer Liver Effects
U.S. EPA (2011) modeled the dose response relationships for liver vacuolation in female rats
using a modified PBPK model from Andersen et al. (1991). Female rats were used based on a
higher response and because data were available for the lower dose groups. The PBPK model
was used to calculate average daily internal liver doses.
U.S. EPA (1980) investigated four dose metrics (hepatic metabolism through the CYP pathway,
GST pathway or combined hepatic metabolism through both pathways, and the concentration
(AUC) of methylene chloride in the liver). Adequate model fits were observed for GST, CYP
and AUC for inhalation data. However, the GST and AUC metrics produced inconsistencies in
dose-response relationship depending on route of exposure. However, these inconsistencies were
not observed using the CYP metric. Therefore, EPA used the internal dose metric based on total
Page 304 of 753

-------
hepatic metabolism through the CYP2E1 pathway (as mg methylene chloride metabolized via
CYP pathway/L liver/day).
U.S. EPA (2011) used seven dichotomous dose-response models in EPA BMDS version 2.0 to
fit to liver lesions incidence and PBPK model-derived internal dose data to obtain rat internal
BMDio and BMDLio values. As noted above, a BMR of 10% was used given a lack of
information on the magnitude of change thought to be minimally biologically significant. The
log-probit model was the best fitting model. The comparison of BMDLios of internal doses from
all seven models are presented in Table 3-18. More details are provided in U.S. EPA (2019h).
Table 3-18. Results of BMD Modeling of Internal Doses Associated with Liver Lesions in
Female Rates from \itselike el al. ( )
Model
KM Dm
liMDLm
\2
(oodness of 111
/rvalue
AIC
Gamma
622.10
227.29
0.48
367.24
Logistic
278.31
152.41
0.14
369.77
Log-logistic
706.50
506.84
0.94
365.90
Multistage (3)
513.50
155.06
0.25
368.54
Probit
279.23
154.52
0.14
369.76
Log-probit
737.93
531.82
0.98
365.82
Weibull
715.15
494.87
0.95
365.88
Source: U.S. EPA (2011), Table 5-6, pg. 193
AIC = Akaike information criterion
EPA obtained the human-equivalent internal BMDLio by dividing the internal rat dose metric by
a pharmacokinetic scaling factor based on the ratio of BW3/4 (scaling factor of 4.09) because
EPA lacked information on methylene chloride's pharmacokinetic differences between rats and
humans. Use of BW3/4 represents EPA's general understanding that metabolic clearance scales
allometrically across species. A probabilistic PBPK model for methylene chloride in humans was
adapted from David et al. (2006) and used with Monte Carlo sampling to calculate distributions
of chronic HECs (mg/m3) associated with the internal BMDLio.
EPA used the 1st percentile to account for susceptibility from the toxicokinetic variability among
humans related to differences in metabolism. Using the 1st percentile, EPA reduced the
intraspecies uncertainty factor (UFH) from 10 to 3. The remaining UFH of 3 accounts for any
toxicodynamic differences among humans. EPA's use of the human toxicokinetics data
distribution is similar to using data-derived extrapolation factors (DDEFs) because it uses
information more specific to methylene chloride hazard. DDEFs are suggested by agency
guidance as preferable to default UFs (EPA. 2.014b). The 5th percentile is very similar (21.3
mg/m3) to the 1st percentile (17.2 mg/m3). The mean is 48.5 mg/m3 (within an order of magnitude
of 3 times higher than the 1st percentile).
Page 305 of 753

-------
Although EPA chose to use the HEC value modeled from Nitschke et al. (1988a). the HEC
modeled from Aiso et al. (2014a) for basophilic cell foci is essentially the same as the value for
vacuolation from Nitschke et al. (1988a) using the same PBPK models and similar assumptions.
See Table 3-19 for the comparison of the modeled values.
Table 3-19. BMD Modeling Results and HECs Determined for 10% Extra Risk, Liver Endpoints
from Two Studies
Internal
dose
metric11
Sex.
Species
Kml point
BMI)
model1'
Animal
liMDI.in"
Human
BMDLio"1
Resulting ///:('
Reference
Liver CYP
metabolism
Female
rat
Vacuolation
log-
probit
531.8
130.0
17.2 mg/m3
[First
percentile]f
Nitschke et al.
(1988a)g
Acidophilic
cell foci
gam-r
645.5
157.4
98.2 mg/m3
Aiso et al.
(2014a)
Basophilic
cell foci
log
114.2
27.85
17.3 mg/m3
a mg methylene chloride metabolized via CYP pathway /Liter of liver tissue /day
b See BMD modeling report for model definitions and details.
0 Animal BMDLio refers to the BMD-model-predicted rat internal dose and its 95% lower confidence limit, associated
with a 10% ER for the incidence of tumors; units are those for the identified dose metric, described in footnote "a".
d When the dose metric is the rate of production of the presumed toxic metabolite (mg/kg/d or mg/L/day), allometric
scaling is applied to adjust for the fact that humans are expected to detoxify the metabolite more slowly than rats. A rat
BMDLio divided by (BWhuman/BWrat)25 = 4.1. Units are the same as for the Animal BMDLio.
e HEC is the 1st percentile of a distribution obtained by determining the exposure concentration for each individual in a
simulated population that is predicted to yield an internal dose equal to the (internal) Human BMDLio; with use of the 1st
percentile the intra-human UF can be reduced from a standard value of 10 to 3, to account for remaining variability in
pharmacodynamic sensitivity.
f For comparison with 1st percentile the fifth percentile and mean values are 21.3 and 48.5 mg/m3, respectively.
gResults of BMD modeling for this study are presented in U.S. EPA (20.1.1').
EPA applied a composite UF of 10 for the chronic inhalation benchmark MOE, based on the
following considerations:
1)	Interspecies uncertainty/variability factor (UFa) of 3
to account for species differences in animal to human extrapolation an interspecies
uncertainty/variability factor of 3 (UFa) was applied for toxicodynamic differences
between species. This UF is comprised of two separate areas of uncertainty to account for
differences in the toxicokinetics and toxicodynamics of animals and humans. In this
assessment, the toxicokinetic uncertainty was accounted for by the PBPK modeling. As
the toxicokinetic differences are thus accounted for, only the toxicodynamic uncertainties
in extrapolating from animals to humans remain, and an UFa of 3 is retained to account
for this uncertainty.
2)	Intraspecies uncertainty/variability factor (UFh) of 3
to account for variation in sensitivity within human populations an intraspecies
uncertainty/variability factor of 3 (UFh) was applied for toxicodynamic differences in the
human population. This UF is comprised of two separate areas of uncertainty to account
Page 306 of 753

-------
for variation in the toxicokinetics and toxicodynamics of the human population because
humans of varying gender, age, health status, or genetic makeup might vary in response
to methylene chloride. In this assessment, the toxicokinetic variation in humans was
accounted for by the probabilistic PBPK model using Monte Carlo sampling of
distributions for the following variables: physiological, tissue volume, partition
coefficient and metabolism (including CYP 2E1) parameters. EPA selected the HEC
associated with the first percentile among humans. As the toxicokinetic differences are
thus accounted for, only the toxicodynamic variability in the human population remains,
and an UFa of 3 is retained to account for this variability.
3) A LOAEC-to-NOAEC uncertainty factor (UFl) of 1
A BMDL, considered to be equivalent to a NOAEL(C) was calculated from Nitschke et
al. (1988a) and therefore an UF of 1 is applied.
Cancer
EPA modeled dose-response relationships for tumor incidence in rodents observed in two
studies, Aiso et al. ( ) and NTP (1986). using the mouse PBPK model of Marino et al.
(2006). Because metabolites of methylene chloride produced by the GST pathway are primarily
responsible for methylene chloride carcinogenicity in mouse liver and lungs and based on the
assumption that metabolites are reactive enough that they don't have substantial distribution
outside the liver, the internal tissue-dose metrics used were daily mass of methylene chloride
metabolized via the GST pathway per unit volume of liver and lung, respectively. When lung
and liver tumors were combined to calculate BMDs and BMDLs for a holistic combination of
tumors, a whole-body GST metric was used that essentially combined the lung and liver internal
doses. Using species-specific information on GST activity in the PBPK models accounts for
differences in GST and GSTT1 activity between mice and humans and among humans. Although
the CYP pathway is considered important at lower concentrations, EPA assumed that there is
some non-zero GSTT1 activity even at low concentrations because there is a possibility of
reaction between methylene chloride and GST/GSH when these molecules are present.
For other tissues (subcutis and mammary gland), there is too little information to determine the
relevant dose metric. For example, genotoxicity and mechanistic studies have not included
mammary tissues. Therefore, these tumors were modeled using the estimated area under the
curve (AUC) of methylene chloride from the Aiso et al. (2014a) data.
U.S. EPA (2.011) also modeled the dose response from mammary tumors observed in NTP
(1986) and details are presented in U.S. EPA (2011). Both NTP (1986) and Aiso et al. (2014a)
observed mostly benign mammary tumors.
EPA obtained the human-equivalent internal BMDLio by dividing the internal mouse dose metric
by a pharmacokinetic scaling factor based on the ratio of BW3 4 (scaling factor of 7) because
EPA lacked information on methylene chloride's pharmacokinetic differences between mice and
humans. Use of BW3/4 represents EPA's general understanding that metabolic clearance scales
allometrically across species. A probabilistic PBPK model for methylene chloride in humans was
adapted from David et al. (2006) and used with Monte Carlo sampling to calculate distributions
of chronic HECs (mg/m3) associated with the internal BMDLio.
Page 307 of 753

-------
Table 3-20 presents the best model fits for several tumor types for multiple cancer endpoints
from Aiso et al. (2014a) and for lung and liver tumors from NTP (1986). BMDLios of internal
doses are presented along with IURs. In addition, the HECs for terminal bronchiole hyperplasia
are also presented for context. Hyperplasia occurred at concentrations higher than lung tumors
and is not expected to be a precursor to the tumors observed. See U.S. EPA (2019h) for other
model results of the tumor types identified below.
Based on the results of these model fits, EPA chose to use the IUR of 1.38 x 10"9 per |ig/m3
based on NTP (1986) in the current risk evaluation because EPA determined that the combined
liver and lung tumor response is relevant for humans and it is the most sensitive of the best-
fitting models for the malignant tumors. Modeling the same tumor types using Aiso et al.
(2014a) results in a very similar IUR of 1.30 x 10"9 per |ig/m3. Although mammary gland and
subcutis tumors yielded higher IURs, there is less certainty about these tumors. The chosen IUR
differs from the IUR of 1 x 10"8 per |ig/m3 recommended in the IRIS assessment (U.S. EPA.
2011) for two reasons. First, the current IUR is used only in the occupational assessment, and
therefore, the value was adjusted from a 24-hr value to one applicable to a workweek of 8 hours
per day, 5 days per week. Second, because the IUR is based on the lower 95% confidence limit,
EPA considers the value to adequately include risk for the GSTT1 +/+ population and that the
previous IUR was more conservative than necessary because it combined both the GSTT1 +/+
population and the lower 95% confidence limit.
Appendix I presents additional information regarding the dose-response modeling steps used to
estimate the cancer slope, and the supplemental document Methylene Chloride Benchmark Dose
and PBPK Modeling Report (EPA. 2019h) presents more details on the models used.
Page 308 of 753

-------
Table 3-20. BMD Modeling Results and Tumor Risk Factors/HECs Determined for 10% Extra Risk, Various Endpoints From Aiso et
al. ( ) and N I P ( )
lnlerii;il
doso
hum ric1
Sox.
Species
r.ndpoini
(Asio slud\. unless
"(MP)")
ISM 1)
model1'
Auiuiiil
mini.
1 III lllilll
IJMI)l.|.,!,jl
1 III lllilll
liiiiKir risk
liiclor
Mesin hum;
dose from
expos
Mixed
population
n inleniiil
1 hk/iii''
IIIV1
GST +/+
Resulting liu
or ///
Mixed
population
niiin ii Rifi^/nri1
X ' (nifi m
GST +/+
Slowly
perfused
AUC
(methylene
chloride)
Male rat
Subcutis
liip-nr


in
1.59 x 10"5
Not
significant l\
different
from mixed
population
5 "(> Id'
Not significantly
different from
mixed population
iiis|2-i'
mi. -
mi.
in
1 4lJ lu-
Mammary Gland
(F/A)
Inn
:i.(. (K.

. -(. in
5'JS lu
nisil-r
:u5 ^5
:<)5 ^5
4 X~ III
""4 lu
Mammary Gland
(F/A/AC)
\o
1(.
i(.
^ "4 lu
5^5 lu
nisil-r
::: ^i
::: ^i
4 5(1 lu
" 15 lu
Subcutis or
Mammary Gland
(F/A)
multi-tumor
78.802
78.802
1.27 x 10"3
2.02 x 10"8
Subcutis or
Mammarv Gland
(F/A/AC)
multi-tumor
81.265
81.265
1.23 x 10-3
1.96 x to-8
Female
rat
Subcutis or
Mammarv Gland
(F/A/AC)
pro
166.68
166.68
6.00 x 10"4
9.54 x K)-"
msl 1 -r
123.7
123.7
8.08 x 10"4
1.29 x in-*
Page 309 of 753

-------
Inleriiiil
dose
mel ric1
Sox.
Species
r.ndpoinl
(Asio slii(l\. unless
"iNii'fi
ISM 1)
model1'
Auiuiiil
mini.
1 III lllilll
IJMI)l.|.,!,jl
1 III lllilll
liiiiKir risk
I'iiclor
Mean hum;
dose IVoin
expos
Mixed
populiilion
n inleniiil
1 iiiii/nri
IIIV1
GST +/+
Resulting liu
or III
Mixed
populiilion
niiin 11 KlMu/nri 1
X ' (Iiifi 111
GST +/+
Liver GST
Male
mice
Liver tumor
lnl-r
413.06
59.01
1.70 x 10"3
6.65 x 1()-'
1.17 x 10"6
1.13 x 10"9
1.98 x 10"9
mst2-r
593.21
84.74
1.18 x 10-3
7.58 x lO"10
1.38 x lO"9
Liver tumor (NTP)
lnl-r
740.82
105.8
9.45 x 10"4
6.28 x 10"10
1.11 x 10"9
msl 1 -r
544.51
77.79
1.29 x 10"3
8.55 x 10"10
1.50 x lO"9
Female
mice
Liver tumor
pro
1332.8
190.40
5.25 x 10"4
3.49 x 10"10
6.14 x 10"10
mst2-r
762.31
108.90
9.18 x 10"4
6.11 x 10"10
1.07 x lO"9
Lung GST
Male
mice
Lung tumor
pro
115.93
16.56
6.04 x 10"3
4.39 x 10"8
7.75 x 10"8
2.65 x K)-i"
4.68 x 10"10
mst 1 -r
55.91
7.987
1.25 x lO"2
5.50 x lO"1"
9.70 x lO"10
Lung tumor (NTP)
msl 1 -r
48.646
6.949
1.44 x 10 -
6.32 x 10"10
1.12 x 10"9
Female
mice
Lung tumor
mst2-r
223.47
31.92
3.13 x 10"3
4.39 x 10"8
7.75 x 10"8
1.38 x 10"10
2.43 x 10"10
TB hyperplasia
msl3-r
411.28
58.75
n/a
7.75 x 104
mg/m3
5.73 x 104 mg/m3
Whole bodv
GST
Male
mice
Liver or lung tumor
multi-tumor
8.217
1.174
8.52 x 10"2
1.53 x 10"8
2.68 x 10"8
1.30 x 10"9
2.28 x 10"9
Liver or lung (NTP)
7.753
1.108
9.03 x 10"2
1.38 x 10"'
2.42 x lO"9
Female
mice
Liver or lung tumor
25.302
3.615
2.77 x 10"2
4.23 x 10"10
7.41 x 10"10
a Tissue-specific dose-units = mg dichloromethane metabolized via GST pathway fL tissue (liver or lung)/day; whole-body dose units = mg dichloromethane metabolized via GST
pathway in lung and liver/kg-day; AUC(methylene chloride) = mg-h/L tissue; all metrics are daily averages given a - week exposure per bioassay conditions (animal dosimetry) or 8
h/d, 5 d/w workplace exposure scenario (human dosimetry).
b Models cited in the table include: lnl-r = Log-Logistic-restricted; lnp-ur = log-Probit-unrestricted; log = Logistic; mstl, 2 or 3 -r = Multistage-restricted (mst-r); from degree 1 to
degree 3 (# dose groups - 1); multi-tumor = Multi-tumor (MS combo); pro = Probit; See the supplemental file Methylene Chloride Benchmark Dose and PBPKModeling Report
(EPA. 2019h) for additional details.
c Animal BMDLio refers to the BMD-model-predicted mouse or rat internal dose and its 95% lower confidence limit, associated with a 10% ER for the incidence of tumors; units are
those for the identified dose metric, described in footnote "a".
d When the dose metric is the rate of production of the presumed toxic metabolite (mg/kg/d), allometric scaling is applied to adjust for the fact that humans are expected to detoxify
the metabolite more slowly than mice and rats. A mouse BMDLio is divided by (BWhumm/BWmouse)0 25 = 7 and a rat BMDLio divided by (BWhumm/BWrat)0 25 = 4.1. When the metric
is the concentration (AUC) of a chemical, no adjustment is made. Units are the same as for the Animal BMDLio.
e Dichloromethane tumor risk factor (extra risk per unit internal dose) derived by dividing the BMR (0.1) by the allometric-scaled human BMDLio. Units are l/(BMDLio units) for
corresponding tissues/endpoints.
f Human inhalation risk is the product of the mean internal dose and the tumor risk factor. The HEC for the non-cancer response (hyperplasia) is the 1st percentile of a distribution
obtained by determining the exposure concentration for each individual in a simulated population that is predicted to yield an internal dose equal to the (internal) Human BMDLio.
Page 310 of 753

-------
3.2.5.2.3 Route to Route Extrapolation for Dermal PODs
EPA did not identify toxicity studies by the dermal route that were adequate for dose-response
assessment. Dermal candidate values, therefore, were derived by route-to-route extrapolation
from the inhalation PODs as introduced under Section 3.2.5.2 (Approach and Methodology).
Inhalation studies were used because the toxic moieties are metabolites of methylene chloride;
inhalation and dermal routes are similar because neither one includes a first pass through the
liver (a site of high metabolic activity) before entering the general circulation. Furthermore, the
inhalation studies are already used to calculate risks for the inhalation route.
Inhalation PODs were extrapolated using models that incorporate volatilization, penetration and
absorption and use a methylene chloride permeability coefficient from an in vitro study (Schenk
et at.. 2018) using pig skin. See Section 2.4.2.3.1 and Risk Evaluation for Methylene Chloride
(Dichloromethane, DCM) CASRN: 75-09-2, Supplemental Information on Releases and
Occupational Exposure Assessment (EPA. 2019b) for details regarding the models used.
The inhalation PODs were extrapolated using a POD based on either human data (i.e., acute
exposures) or the BMDLhec (a value from animals adjusted to account for animal to human
extrapolation using the PBPK model). The equations for extrapolating from inhalation PODs to
the dermal route then must account for human inhalation and body weight:
For non-cancer effects:
dermal POD = inhalation POD [mg/m3] x inhaled volume (m3) ^ body weight (kg)
For cancer:
dermal slope factor = IUR [per mg/m3] ^ inhaled volume (m3) x body weight (kg)
where the inhaled volume was the ventilation rate 1.25 m3/hr (slightly higher than light activity)
(Niosh. 1976) multiplied by the appropriate exposure duration (1.5 hours from Putz et al. (1979))
for acute endpoints, or 20 m3 per day for the chronic endpoint) and a body weight of 80 kg (EPA.
2 ). Note that assuming a higher inhalation rate based on moderate intensity work for the
purposes of route-to-route POD extrapolation would result in a higher POD that may not be
appropriate or adequately health protective for all exposure scenarios.
PODs were derived from Putz et al. (1979) for a range of inhalation exposure durations.
However, EPA used the duration from the experimental study (1.5 hrs) and the associated air
concentration (a LOAEC of 195 ppm or 696 mg/m3) for extrapolation to the dermal route.
There is uncertainty in extrapolating the hazard endpoints across routes. Although some
neurotoxicity may result from absorption through nasal passages to the brain, EPA does expect
that dermal exposure can also result in neurotoxicity. Furthermore, there is uncertainty regarding
the likelihood that dermal exposure will result in lung cancer, but because humans may
experience different cancers than rodents, EPA has assumed that the slope factor of the
combined tumor types can be considered generally representative of the potential for cancers of
other types.
Page 311 of 753

-------
EPA has also identified irritation and burns from dermal contact. Although these are not
quantitatively assessed in the risk evaluation, they are an important consideration for risk
characterization and are noted in Section 4.3 (Human Health Risk).
3.2.5.3 PODs for Human Health Hazard Endpoints and Confidence Levels
Table 3-21 summarizes the PODs derived for evaluating human health hazards from acute and
chronic inhalation scenarios. Table 3-22 summarizes the PODs extrapolated from inhalation
studies to evaluate human health hazards from acute and chronic dermal scenarios. EPA has also
determined confidence levels for the acute, non-cancer chronic and cancer chronic values used in
the risk evaluation. These confidence levels consider the data quality ratings of the study chosen
as the basis of dose-response modeling and also consider the strengths and limitations of the
body of evidence including the strengths and limitations of the human, animal and MOA
information to support the endpoint both qualitatively and quantitatively.
Confidence Levels
For the acute inhalation endpoint, the value used for this risk evaluation is from Putz et al.
(1979), a medium quality double-blind study. In addition, there is consistency in observing CNS
effects in humans, which is supported by several studies in animals. However, the study used a
single concentration and there is uncertainty in converting among exposure durations. Overall,
there is medium confidence in this endpoint.
For the chronic non-cancer endpoint, there is limited information in humans regarding liver
endpoints but a consistent and full set of studies of liver effects in animals. The dose-response
modeling is based on a chronic study given a high data quality rating with a chronic POD that is
supported by a second high-quality study. Thus, EPA has medium confidence in the chronic non-
cancer endpoint based on liver effects.
For the chronic cancer endpoint, there are some inconsistencies in the epidemiological data and
uncertainty in concordance of cancers between animals and humans. However, there is good
consistency of results in animals across multiple studies and support from genotoxicity studies
that identify effects in the presence of GSTT1. Furthermore, use of PBPK models account for
differences in GST and GSTT1 activity between mice and humans and among humans.
Furthermore, a high-quality chronic cancer bioassay is used as the basis of the dose-response
modeling. Thus, EPA has medium confidence in the chronic cancer endpoint and dose-response
model used in this risk evaluation.
Page 312 of 753

-------
Table 3-21. Summary of PODs for Evaluating Human Health Hazards from Acute and
Chronic Inhalation Scenarios
l'A|)OMIIV
l)iir;ilion for
Risk An;il\sis
ll;i/;inl Value
r.iToci
Tolill
I nccrl;iin(\
l";ic(or (I I") for
lieiichm;irk
MOI.
Reference
CHRONIC
EXPOSURE
IUR
40 hrs/wk:
1.38 x 10"6 per mg/m3
Liver and lung tumors
Not applicable
NTP (.1.986)
1st percentile HEC i.e., the HEC99
24 hrs/day:
17.2 mg/m3
(4.8 ppm)
Liver effects
UFa=3;
UFh=3;
UFl=1
Total UF=10
Nitschke et
al.(l 988a)
ACUTE
EXPOSURE
15-min: 478 ppm (1706 mg/m3)
1-hr: 240 ppm (840 mg/m3)
8-hrs: 80 ppm (290 mg/m3)
Impairment of CNS
7% I visual peripheral
performance at 1.5 hrs
(p<0.01)
UFa=1;
UFh=10;
UFl=3
Total UF=30
CNS data from
Putz et al. (1979):
Conversion of
PODs based on ten
Berge et al. (.1.986)
Table 3-22. Summary of PODs for Evaluating Human Health Hazards from Acute and
Chronic Dermal Exposure Scenarios	
l'A|)OMII'e
Dunilion for
Risk An;il\sis
llii/iii'd Vsilue I seel in Risk Assessment
11 flee I
loliil 1 iieei(;iiii(>
l-iiclor (I I") for
lioiichniiirk MOI
CHRONIC
EXPOSURE
Dermal Slope Factor
extrapolated from the IUR:
1.1 x 10"5 per mg/kg
Liver and lung tumors
Not applicable
1st percentile human equivalent dermal dose
(HEDD) i.e., the HEDD99 extrapolated from
inhalation:
2.15 mg/kg
Liver effects
UFa=3;
UFh=3;
UFl=1
Total UF=10
ACUTE
EXPOSURE
Extrapolated from inhalation
POD =16 mg/kg
Impairment of the
CNS
UFa=1;
UFh=10;
UFl=3
Total UF=30
Page 313 of 753

-------
4 RISK CHARACTERIZATION
Environmental and human health risk estimate approaches and results for specific exposure
scenarios are presented in sections 4.2 and 4.3, respectively. The aforementioned sections
describe the basis for the risk conclusions presented in section 4.1.
4.1 Risk Conclusions
4.1.1 Summary of Environmental Risk
EPA's analysis of environmental risk, in Section 4.2, identified risk to aquatic organisms and
sediment-dwelling species (acute RQ > 1, or a chronic RQ > 1 and 20 days or more of
exceedance for the chronic COC). EPA identified risk to aquatic organisms near four recycling
and disposal facilities and one WWTP and identified risk to sediment-dwelling species near one
recycling and disposal facility. These facilities are presented in Table 4-1.
EPA's analysis, did not identify risk (acute RQ < 1, and chronic RQ < 1 or chronic RQ > 1 with
less than 20 days of exceedance) for facilities in other conditions of use including manufacturing,
import and repackaging, processing as a reactant, processing and formulation, use in
polyurethane foam, use in plastics manufacturing, CTA film manufacturing, lithographic printer
cleaning, spot cleaning, "other" unspecified conditions of use, and Department of Defense uses.
In ambient water, EPA's analysis did not identify risk (acute RQ < 1, and chronic RQ < 1 or
chronic RQ > 1 with less than 20 days of exceedance) to aquatic organisms or sediment-dwelling
species from acute or chronic exposures; therefore, the risks identified for the five facilities
mentioned above are likely localized to surface water near the facility.
Recycling and Disposal
Four out of 16 recycling and disposal facilities had releases of methylene chloride to surface
water that indicate risk to aquatic organisms. One out of these 16 facilities also had a release that
indicated risk to sediment-dwelling species. Veolia es Technical Solutions, which transfers
methylene chloride to Clean Harbors POTW, had an indirect release to surface water indicating
risk from acute exposure with an acute RQ of 6.88. Veolia es Technical Solutions also had risks
from chronic exposure for multiple taxonomic groups, with a chronic RQ for amphibians of 201
with 250 days of exceedance, for fish of 119 with 250 days of exceedance, and for aquatic
invertebrates of 10.1 with 200 days of exceedance, respectively. Additionally, the data showed
that there is risk to sediment dwelling organisms near Clean Harbors POTW due to chronic
exposure with RQ =10.1 with 200 days of exceedance. Johnson Matthey West Deptford and
Clean Harbors Deer Park both had indirect releases to Clean Harbors Baltimore with chronic
RQs for amphibians of 1.32 with 53 days of exceedance and 1.32 with 53 days of exceedance,
respectively. Clean Water of New York Inc Staten Island, which may be releasing methylene
chloride into an estuarian environment, had chronic RQs for amphibians of 3.92 and for fish of
2.34, both with 20 days of exceedance.
Wastewater Treatment Plants (WWTP)
One out of 29 WWTPs had a release of methylene chloride to surface water that indicated risk to
aquatic organisms. Long Beach WPCP Long Beach had a direct release to an estuarian
Page 314 of 753

-------
environment that indicated risk for fish from chronic exposure, with RQs of 2.00 with 365 days
of exceedance.
Page 315 of 753

-------
Table 4-1. Final Summary of Facilities Showing Risk from Acute and/or Chronic Exposure from the Release of Methylene Chloride;
RQ Greater Than One are Shown in Bold	
N;i nil'.











l ocution. ;iml

Modeled I'aciliU









II) ol' Ac(i\e

oi* Indusln
I'.-l-AST
Annual

l)ail\
'ym


l)a\s of

Releaser
Release
Seclor in I-'.-
\\ alerhod\
Release
l)a\s of
Release
S\\(

<<>(
llxceedance

l-acililv'
Media1'
1-'AST*'
Tj pe'1
(kii>
release"'
(kg/da>)'
ipplH"
COC Tjpe
(ppl>)
(da\s/\ nh
RQ
OES: Recycling and Disposal
JOHNSON
MATTHEY
Non-
POTW
WWT
Receiving
Facility: Clean
Harbors of
Baltimore, Inc;





Chronic
Amphib.
90
53
1.32
WEST
Surface
620
250
2
118.56
Chronic Fish
151
27
0.79
DEPTFORD, NJ
water
Chronic Invert.
1,800
0
0.07
NPDES:
NJ0115843










POTW (Ind.)





Acute Amphib.
2,630
N/A
0.05
CLEAN
HARBORS

Receiving





Chronic
Amphib
90
53
1.32
DEER PARK
Non-
Facility: Clean
Surface
water




Chronic Fish
151
27
0.79
LLC LA
POTW
Harbors of
522
250
2
118.56
Chronic Invert.
1,800
0
0.07
PORTE, TX
WWT
Baltimore, Inc;




Acute
Amphib.



NPDES:
TX0005941

POTW (Ind.)





2,630
N/A
0.05
VEOLIA ES







Chronic
90
250
201
TECHNICAL

Receiving
Facility: Clean
Harbors; POTW
(Ind.)





Amphib.
SOLUTIONS
Non-
Surface
water




Chronic Fish
151
250
119
LLC
POTW
76,451
250
306
18100
Chronic Invert.
1,800
200
10.1
MIDDLESEX,
NJ NPDES:
NJ0127477
WWT




Acute
Amphib.
2,630
N/A
6.88
CLEAN
WATER OF
NEW YORK
INC STATEN
ISLAND, NY
NPDES:







Chronic
Amphib
90
250
0.31




250
0.01
27.94
Chronic Fish
151
0
0.19

Active Releaser


Chronic Invert.
1,800
0
0.02
Surface
Water
(Surrogate):
NPDES
Still body
2.38



Acute
Amphib
2,630
N/A
0.01

NJ0000019





Chronic
Amphib
90
20
3.92
NY0200484




20
0.12
352.94







Chronic Fish
151
20
2.34








Chronic Invert.
1800
0
0.20
Page 316 of 753

-------
Name.











locution. iiiid

Modeled I'aeiliU









II) ol' Aeli\e

oi* Indusln
l.-l AST
Anniiiil

l)ail\
'ym


I);i\s of

Releaser
Release
Seelor in H-
\\ alerl>od\
Release
l)a\s of
Release
SWC

COC
llxeeedanee

l-aeililv'
Media1'
1-'AST*'
Tj pe'1
(kii)
release"'
(kii/(l;n)'
(ppl))-
COCTjpe
(ppl>)
(da\s/\ nh
RQ








Acute
Amphib
2,630
N/A
0.13
OES: WWTP








Chronic
90
365
3.35








Amphib.
LONG BEACH




365
7
301.46
Chronic Fish
151
365
2.00

Active Releaser:
NPDES


Chronic Invert.
1,800
0
0.17
(C) WPCP
LONG BEACH,
Surface
Water
Still water
2,730



Acute
Amphib
2,630
N/A
0.11
NYNPDES:

NY0020567








NY0020567




20
136.49
5878.12
Amphib
-
-
-





Chronic Fish
-
-
-








Chronic Invert.
-
-
-








Acute











Amphib.



a. Facilities actively releasing methylene chloride were identified via DMR and TRI databases for the 2016 reporting year.



b. Release media are either direct (release from active facility directly to surface water) or indirect (transfer of wastewater from active facility to a receiving POTW or non-
POTW WWTP facility). A wastewater treatment removal rate of 57% is applied to all indirect releases, as well as direct releases from WWTPs.


c. If a valid NPDES of the direct or indirect releaser was not available in EFAST, the release was modeled using either a surrogate representative facility in EFAST (based
on location) or a representative generic industry sector. The name of the indirect releaser is provided, as reported in TRI.



d. EFAST uses ether the "surface water" model, for rivers and streams, or the "still water" model, for lakes, bays, and oceans.



e. Modeling was conducted with the maximum days of release per year expected. For direct releasing facilities, a minimum of 20 days was also modeled.

f. The daily release amount was calculated from the reported annual release amount divided by the number of release days per year.



g. For releases discharging to lakes, bays, estuaries, and oceans, the acute scenario mixing zone water concentration was reported in place of the 7Q10 SWC.

h. To determine the PDM days of exceedance for still bodies of water, the estimated number of release days should become the days of exceedance only if the predicted
surface water concentration exceeds the COC. Otherwise, the days of exceedance can be assumed to be zero.




Page 317 of 753

-------
4.1.2 Summary of Risk Estimates for Inhalation and Dermal Exposures to
Workers
Table 4-2 summarizes the risk estimates for inhalation and dermal exposures for all occupational
exposure scenarios. Risk estimates that exceed the benchmark (i.e., MOEs less than the
benchmark MOE or cancer risks greater than the cancer risk benchmark) are highlighted by
bolding the number and shading the cell. U.S. EPA shaded the cells for risk estimates that are not
calculated i.e., short-term exposures estimates for chronic endpoints and that are not assessed
i.e., PPE use for ONUs. The risk characterization is described in more detail in Sections 2.4.1
and 4.3.2 and specific links to the exposure and risk characterization sections are listed in Table
4-2 in the column headed Occupational Exposure Scenario.
Page 318 of 753

-------
Table 4-2 Summary of Risk Estimates for Inhalation and Dermal Exposures to Workers by






Risk 1 !s|iinalos lor \o I'I'I
Risk 1 !siinialcs w illi I'M






\ciile
Chrome

\cnlc
( limine

Life C\cle
Siauc Calcuor\

(Jcciipalioiial
1 \poMiic Scenario

1 \poMiic
1 Aposiiic
Level
\on-
c: nicer
(bench-
\on-
c; ii icc i"
(hcncli-
Cancer
\on-
c; nicer
(he nc li-
\on-
caiicer
(he nc li-
Cancer
Siihcalcuor\
Population
Route and
1 Juration
(he nc li-
ma rk
ID 1
(bench-
mark
ID 1





mark
mark
ma rk
ma rk






\1( )l:
\l( )l:
\1()L
\l( )l:






'<))
10)

'in
10)

Manufacturing
Manufacturing
Seclimi 2 4 12 1 and


Coin ml
7y5
2u7
2.UUE-U7
1 ')X"X
51(4
x (mi :-(>-
Domestic

4.3.2.1.2-
Worker
Inhalation
Tendency
(APF 25)
(APF 25)
(APF 25)
manufacturing

Manufacturing
Exposure
8-hr TWA
High-
End
63
16
3.26E-06
1575
(APF 25)
409
(APF 25)
1.30-07
(APF 25)



Worker
Inhalation
15-min
TWA*
Central
Tendency
\-<>
\ (
\ (
44<>5
( \H' 25)
\ (
\ (



High-
End
l) *
\ (
\ (
2 '2
( \\>\: 25)
\ (
\ (



Worker
Dermal
High-
End
"1
1.4
x<.<>i :-<)(.
(I'L 51
28
(I'F 20)
1.74E-06
(PF5)



ONU
Inhalation
8-hr TWA
Central
Tendency
"<>5
2(1"
2 uuL-ir
\ \
\ \
\ \




Inhalation
Central
Tendency









ONU
15-min
TWA*
r<>
\ (
\ (
\ A
\ \
\ A
Manufacturing/
Import
Import
Section 2.4.1.2.4 and
4.3.2.1.5 -
Worker
Inhalation
Central
Tendency
33
X.54
4X41:-()(,
X22
( \\>\: 25)
213
( \I'F 25)
-


Repackaging
8-hr TWA
High-
End
: i
u 55
l> "4L-U5
53
( \\>\: 25)
14
( \IT25)
-



Worker
Inhalation
1-hr
TWA*
Central
Tendency
4 "
\ (
\ (
1 IX
( \\>\: 25)
\ (
\ (



High-
End
2 (
\ (
\ (
(4
( \\>\: 25)
\ (
\ (



Worker
Dermal
High-
End
" 1
1 4
s i.'^i :-(K.
'5(>
(I'L 51
2X
(PI 2(ii
i "4i :-(>(.
(I'l' 51



ONU
Inhalation
8-hr TWA
Central
Tendency
33
X.54
4X41:-()(,
\ A
\ \
\ A




Inhalation
Central









ONU
1-hr
TWA*
Tendency
4 "
\ (
\ (
\ \
\ \
\ \
Processing/
Processing as a
reactant
Intermediate in industrial gas
manufacturing (e.g., manufacture of
fluorinated gases used as refrigerants)
Section 2.4.1.2.2 and
4.3.2.1.3 - Processing
as a Reactant
Worker
Inhalation
8-hr TWA
Central
Tendency
178
46
8.95E-07
4441
(APF 25)
1154
(APF 25)
-
Condition of Use
Page 319 of 753

-------
l.ilc (>clc
Siauc ( alcuors
Suhcalcuor\
()ccupalioiial
1 Aposurc Scenario
Population
1 Aposurc
Route and
1 )uralioii
1 Aposurc
I.CNCl
Risk 1 :siuiialcs for \o I'M!
Risk 1 !siiniales w nli PPI
\cuic
Nou-
cauccr
(hcuch-
mark
\l( )l:
-n i
Chronic
Noii-
caucer
(hcuch-
mark
\l( )l:
Id)
Cancer
i he uc li-
ma rk
|u i
\cuic
\oii-
cauccr
i he uc li-
ma rk
\1()L
'i)i
( limine
\ou-
caiiccr
i he uc li-
ma rk
\I()L
ID)
(auccr
(bench-
mark
ID )
llidi-
1 lid

o."
" 5
(i~
( \PI; 251
r
i \PI" 25)

Worker
Inhalation
15-niiii
1 W \ *
Point
1 !s| 1IIKIIC
4<)
\ (
\ (
122
( \PL 25)
\ (
\ (
luicrnicdialc fur pcsiicidc. fcriili/cr. and
oilier auriciiliural elieimeal
iiiaiiiilaeliii'Miu
Worker
Dermal
1 liuli-
1 lid
" 1
1 4
s (i'ji :-()(
'5(>
< PI 51
2S
(PI 20)
i "4i:-()(.
(PL 5)
<>\l
Inhalation
X-hrTW \
Central
1 cudciics
rs
4(>
s >>51 :-<>"
\ \
\ \
\ \
llidi-
1 lid
-
ii "
" <>'L-()5
\ \
\ \
\ \
Petrochemical niauiifacliii'iim
Intermediate lor oilier chemicals
<>\l
Inhalation
15-niiii
TW A
Point
1 !s| 1 IIKIIC
4<)
\ (
\ (
\ A
\ \
\ A
Processing/
Incorporated
into formulation,
mixture, or
reaction product
Solvents (for cleaning or degreasing),
including manufacturing of:
	All other basic organic chemical
	Soap, cleaning compound and toilet
preparation
Section 2.4.1.2.3 and
4.3.2.1.4 - Processing
- Incorporation into
Formulation, Mixture,
or Reaction Product
Worker
Inhalation
8-hr TWA
Central
Tendency
:
ii "4
5 5SI :-()5
14'
( \PL 50)
37
( \PI" 50)
2 2 'i:-()(.
( \PL25)
High-
End
1154
H.I4
' SIL-II4
2"
( \PI 5(>i
".()
( \PI 5D)
1 52L-D5
( \PL25)
Worker
Inhalation
15-min
TWA*
Point
Estimate
<) 5
\ (
\ (
237
( \IJI 25)
\ (
\ (
Worker
Dermal
High-
End
" 1
1 4
x<.<)i :-(K.
'5<>
(PL 51
2S
(PI' 20)
i "4i:-()(.
(PL 5)
Solvents (which become part of product
formulation or mixture), including
manufacturing of:
	All other chemical product and
preparation
	Paints and coatings
Propellants and blowing agents for all
other chemical product and preparation
manufacturing
ONU
Inhalation
8-hr TWA
Central
Tendency
:
u "4
5 5SI :-()5
\ \
\ \
\ \
High-
End
(154
u 14
' s 11 :-(>4
\ \
\ \
\ \
ONU
Inhalation
15-min
TWA*
Point
Estimate
<> 5
\ (
\ (
\ \
\ \
\ \

Page 320 of 753

-------






Risk 1 !siimales lor \o I'I'I
Risk 1 !siinialcs w ilh I'M




1 ApoMiie
konic and
1 Juration

\cnic
\on-
Chronic
\on-
Cancer
(he nc li-
ma rk
l<> i
\cnlc
Nun-
( limine
Non-
Cancer
(bench-
mark
ID 1
l.ilc C\cle
SulvaleuoiA
()cciipalioiinl
Population
1 Aposiiic
c; nicer
c; nicer
cm ice i"
caiicer
Siauc ( nlcuor\
1 Aposiiic Scenario
l.e\el
(bench-
(bench-
(he nc li-
(he nc li-





mark
\1()L
'i)i
mark
\1()L
10)
ma rk
\1()L
'())
ma rk
\K)L
10)

Propellants and blowing agents for
plastics product manufacturing











Paint additives and coating additives not
described by other codes











Laboratory chemicals for all other
chemical product and preparation
manufacturing











Laboratory chemicals for other industrial
sectors











Processing aid, not otherwise listed for
petrochemical manufacturing











Adhesive and sealant chemicals in





See the rows above for risk estimates


adhesive manufacturing







Oil and gas drilling, extraction, and
support activities










Processing/
Repackaging
Solvents (which become part of product
formulation or mixture) for all other
Section 2.4.1.2.4 and
4.3.2.1.5 -
Worker
Inhalation
Central
Tendency
33
X.54
4 S4I :-()(
822
(APF 25)
213
(APF 25)
-

chemical product and preparation
manufacturing
Repackaging
8-hr TWA
High-
End
: i
0 55
') "41: -() 5
53
(APF 25)
14
(APF 25)
-



Worker
Inhalation
1-hr
TWA*
Central
Tendency
4 "
\ (
\ (
118
(APF 25)
\ (
\ (



High-
End
: (.
\ (
\ (
64
( \\>\: 251
\ (
\ (

All other chemical product and
preparation manufacturing

Worker
Dermal
High-
End
-.1
1.4
xi.'Ji :-u(.
'5<>
(I'f 5)
:x
(pi :in
i "4i :-(>(.
(I'f 51



ONU
Inhalation
Central
Tendency
33
X.54
4X41 :-(>(.
\ A
\ \
\ A



8-hr TWA
High-
End
: i
() 55
"4L-II5
\ \
\ \
\ \



ONU
Inhalation
1-hr
TWA*
Central
Tendency
4 "
\ (
\ (
\ \
\ \
\ \
Processing/
Recycling
Recycling
Section 2.4.1.2.5 and
4.3.2.1.6-Waste
Worker
Inhalation
8-hr TWA
Central
Tendency
124
32
1.29E-06
3uy2
(APF 25)
803
(APF 25)
-
Page 321 of 753

-------






Risk 1 :siimales lor \o I'M!
Risk 1 !siiniales w illi PPI






\cule
(limine

\cnie
( limine

l.ilc (>ele
Siaue ( aleuors
Siihcaleuor\
()cciipalional
1 Aposnre Scenario
Population
1 Aposnre
koine and
1 Juration
1 Aposnre
Le\el
Non-
cancer
(bench-
Noil-
cancer
(bench-
Cancer
(he nc li-
ma rk
In i
Nun-
cancer
(he nc li-
Nini-
cancer
(he nc li-
Cancer
(bench-
mark
In i





mark
mark
ma rk
ma rk






\1( )l:
\1( )l:
\I()L
\I()L






'i)i
Kii

'())
Mil



Handling, Disposal,
Treatment, and


High-
End
15
4(i
1.38E-05
382
(APF 25)
99
(APF 25)
-


Recycling
Worker
Dermal
High-
End
' (.
(i )?
5.71E-05
90
CAPF 25*)
23
(APF 25)
-



ONU
Inhalation
Central
Tendency
124
'2
1.29E-06
N A
N \
N A



8-hr TWA
High-
End
" 1
1 4
8.69E-06
'5<>
(Pl'5>
28
(PI 2(H
i "4i:-(K.
(PI 51
Distribution in
commerce
Distribution
Distribution
Please see Section 5.2.1.7
Industrial and
commercial use/
Batch vapor degreaser (e.g., open-top,
closed-loop)
Section 2.4.1.2.5 and
4.3.2.1.7-Batch
Worker
Inhalation
Central
Tendency
1 "
(145
J 2 ' E-05
43
( \PP 25)
11
( \PI 25)
3.69E-06
( \PF 25s)
Solvents (for
cleaning or

Open-Top Vapor
Degreasing
8-hr TWA
High-
End
(1 V)
(i |(i
5 2~l -(>4
I'J
( \IJI 5(H
5 1
( API 5(ii
2 1 IL-05
( \PI 251
degreasing)


Worker
Dermal
High-
End
~ 1
1 4
Xi.'Jl :-(K.
'5<>
(PL 51
28
(PL 2(H
1 "41 :-()(
(PL 51



ONU
Inhalation
Central
Tendency
3
(i X"
4 "4L-H5
N A
N \
N A



8-hr TWA
High-
End
u.(4
n.2
' 22L-H4
N A
N \
N A

In-line vapor degreaser (e.g.,
conveyorized, web cleaner)
Section 2.4.1.2.6 and
4.3.2.1.8-
Worker
Inhalation
Central
Tendency
<).(>()
H.I5
2 (.~l -(>4
( \\'\: 5(H
( \PI 5(1)
1 (I4L-II5
( \PI 25)


Conveyorized Vapor
Degreasing
8-hr TWA
High-
End
D.2
t i.(i5
S~l :-(i4
Ki.4
( \PL 5(1)
2 "
( \PI 5ii)
2 in:-(>5
( \PI 25)



Worker
Dermal
High-
End
"1
1.4
s (.'jr-nr.
356
(PL 51
28
(PL 2(H
1.74E-06
(PL 51



ONU
Inhalation
Central
Tendency
1
(i M)
i ^i:-u4
N A
N \
N A



8-hr TWA
High-
End
u '2
(i 1
(. '"i :-(i4
N \
N \
N \

Cold cleaner
Section 2.4.1.2.7 and


Central
1 u4
(i 2"
1 541-114
52
1 '
(. 141:-(.


4.3.2.1.9-Cold
Worker
Inhalation
Tendency
( \PL 5(1)
( \PI 5(H
( \PI 25)


Cleaning
8-hr TWA
High-
End
(i 2<>
(MIS
- osi :-(>4
15
( \IJI 5(H
' X
( \PI 5(1)
2 X'L-()5
( \PI 25)
Page 322 of 753

-------






Risk 1 Snmales lor \o I'M!
Risk 1 !s|iinalcs w illi I'I'I






\cuie
Chronic

\culc
( limine

l.ilc (>ele
Siaue ( ;ileuni'\
SuhcaleuoiA
(Jcciipaliniial
1 ApoMire Scenario
Population
1 Aposure
kouie and
1 Juration
1 Aposure
l.e\el
\ou-
c; nicer
(bench-
\on-
canccr
(hcncli-
Cancer
i he nc li-
ma rk
|0 )
\on-
canccr
i he nc li-
\ou-
cancer
(he nc li-
Cancer
(heneli-
mark
10 )





mark
mark
ma rk
ma rk






\K)L
\k )i:
\I()L
\I()L






'i)i
10)

'0)
10)




Worker
Dermal
High-
End
7.1
1.4
X(.')E-06
36
(PF5)
28
(PF 20)
1.74E-(Jb
(PF5)



ONU
Inhalation
Central
Tendency
I.D4
u.:-
1 54L-04
\ A
\ \
\ A



8-hr TWA
High-
End
i).2l)
DOS
"0XL-04
\ A
\ \
\ A

Aerosol spray degreaser/cleaner
Section 2.4.1.2.8 and
4.3.2.1.10 -
Worker
Inhalation
Central
Tendency
48
12
3.31E-06
1201
(APF 25)
312
(APF 25)
1.32E-07


Commercial Aerosol
Products (Aerosol
8-hr TWA
High-
End
1 '
(1 V,
1 (. 11-04
'2
( \PP 25)
r
( \PI' 50)
(.441 :-()(


Degreasing, Aerosol
Lubricants,
Worker
Dermal
High-
End
4 (>
0 'J
1 '5L-05
4(>
(PI 10)
0
(PI Id)
2 "oi :-o(.
(PL 5)


Automotive Care
Products)
ONU
Inhalation
Central
Tendency
4X
i:
' 'IL-0(,
\ \
\ \
\ \



8-hr TWA
High-
End
1 '
(i v,
1 (. 11-04
\ \
\ \
\ \
Industrial and
Single component glues and adhesives
Section 2.4.1.2.9 and


Central
"4
I.T,
2 I4L-05
1 X(i
4X
x 5(.i :-o~
commercial use/
and sealants and caulks
4.3.2.1.11 -
Worker
Inhalation
Tendency
( \PP 25)
( \PI' 25)
( \PI; 25)
Adhesives and
sealants

Adhesives and
Sealants (spray)
8-hr TWA
High-
End
() 52
(1.14
' <>5L-04
2(>
( \PI' 50)
(. X
(API 50)
1 5X1: -() 5
( \PI; 25)



Worker
Dermal
High-
End
"1
1.4
X(.')i:-o(>
'(.
(PP 5)
2X
(PI' 20)
i "4i :-o(.
(PL 5)



ONU
Inhalation
Central
Tendency
"4
I.T,
: I4L-05
\ A
\ \
\ A



8-hr TWA
High-
End
() 52
0.14
' <>5L-04
\ A
\ \
\ A


Section 2.4.1.2.9 and


Central
2X
7.2
5 "4L-0(,
(>l)2
1X0
2 'in :-o"


4.3.2.1.11 -
Worker
Inhalation
Tendency
i.VPL' 25)
(_YP1; 25)
(_YP1; 25)


Adhesives and
Sealants (non-spray)
8-hr TWA
High-
End
o <;x
o 25
: ioi :-o4
49
(APF 50)
13
(APF 50)
8.37E-06
(APF 25)



Worker
Dermal
High-
End
" 1
1 4
X(.')i:-o(>
36
(PF 5)
28
(PF 20)
1.74E-06
(PF 5)



ONU
Inhalation
8-hr TWA
Central
Tendency
:s
" 2
5 xoi :-()<>
\ \
\ \
\ \
Page 323 of 753

-------






Risk 1 !siimales for \o I'I'I
Risk 1 \uniales w illi PPI
l.ilc (>ele
Siaue ( aleuors
Siihcaleuors
()cciipalional
1 Aposnre Scenario
Population
1 Aposnre
koine and
1 )iiralkin
1 Aposnre
l.e\el
\cnte
\on-
c; nicer
(bench-
mark
\I()L
'i)i
Chronic
Noii-
cancer
iheiich-
mark
\I()L
10)
Cancer
(he nc li-
ma rk
|o )
\cnie
\on-
cancer
(he nc li-
ma rk
\1()L
'())
( limine
\oii-
cancer
(he nc li-
ma rk
\I()L
10)
Cancer
(bench-
mark
10 )





1 liuli-
1 lid
0 52
0.25
' ,)5L-04
\ A
\ \
\ A
Industrial and
commercial use
Pamls and coalnms use and pamls and
coalnm rcnio\ers. iiichidiim liirmliirc
Section 2 4 1 2 In
and 4 ^: i 12 -
Worker
Inhalation
Central
Tcndencs
4.15
l.os
' S'L-o5
|()4
( \PI' 25)
( \PI 25)
i 5 'i:-o(.
( \PI 25)
Pamls ;iik.|
coalnms
rcliiiisher
Painis and ( oalnms
S-hr'I'W \
1 liuli-
1 ikI
II SI)
0.21
2 5SL-04
40
( \PI' 50)
|o '
( \PI 50)
1 (i i|; -(15
( \PI 25)
iiieliidiiiu
commercial


Worker
Dermal
1 liuli-
1 ikI
" 1
1 4
S (i'J| :-()(
i(t
(PI 5)
2S
(PI' 20)
i "4i :-o(.
(pf 5)
p;nill ;ind
coalnm


<>\l
Inhalation
Central
Tcndencs
4 15
1 OS
' s'i: -i 15
\ \
\ \
\ \
renio\ ei's


S-hr'I'W \
1 liuli-
1 ikI
1) Si)
0 21
2 5SI :-()4
\ \
\ \
\ \


Paint and Coating
Removers
Please see Appendix L.

Adhesive/caulk removers
Section 2.4.1.2.11
and 4.3.2.1.13 -
Worker
Inhalation
Central
Tendency
I) I'J
IMI5
s ui :-o4
5
( \PI'50)
2 5
(API' 50)
' v,i:-i)5
( \PI 25)


Adhesive and Caulk
Removers
8-hr TWA
High-
End
oil)
(MP,
2 1 IL-IP
4')
( \PI' 50)
1.'
( \PI' 50)
S44L-05
( \PI 25)



Worker
Dermal
High-
End
4.<>
0 
0 ')
1 '5L-05
4(>
iPI Id)
0
(PL Id)
2 "oi :-o(.
(pf 5)


Automotive Care
Products)
ONU
Inhalation
Central
Tendency
4S
12
' ' 11 :-()(>
\ \
\ \
\ \



8-hr TWA
High-
End
1 '
0 V,
1 (. 11-04
\ \
\ \
\ \
Page 324 of 753

-------






Risk 1 Siimales lor \o I'M!
Risk 1 !siinialcs w illi PPI






\cnic
Chronic

\cnic
( limine

l.ilc (>clc
Siauc ( ;ileuni'\
Siihcalcuor\
()cciipaliinial
1 ApoMirc Scenario
Population
1 ApoMiie
konic and
1 Juration
1 Aposnrc
l.e\el
\on-
c; nicer
(bench-
\on-
canccr
(bench-
Cancer
(he nc li-
ma rk
|0 1
\on-
canccr
(he nc li-
\on-
cancer
(he nc li-
Cancer
(bench-
mark
10 )





mark
mark
ma rk
ma rk






\1( )l:
\1( )l:
\l( )l:
\I()L






'i)i
10)

'()>
10)



Section 2.4.1.2.19


Central
5.1
1.'
' 1 1E-05
128
33
1.24E-(Jb


and 4.3.2.1.14 -
Worker
Inhalation
Tendency
(APF 25)
(APF 25)
(APF 25)


Miscellaneous Non-
Aerosol Industrial
8-hr TWA
High-
End
u '1
DOS
(. 5SL-04
l(.
( \IJI 50)
4o
( ALL 50)
2 63E-05
( YPF 25)


and Commercial Uses
Worker
Dermal
High-
End
4.<>
(1 911
1 '5L-05
4(>
(PI loi
9 0
(PL Id)
2 "o| :-()(
(PL 5)



ONU
Inhalation
Central
Tendency
5 1
1 '
' 1 IL-05
\ \
\ A
\ \



8-hr TWA
High-
End
u '1
DOS
(. 5Si :-()4
\ \
\ A
\ \
Industrial and
commercial use/
Textile finishing and
impregnating/surface treatment products
Section 2.4.1.2.12
and 4.3.2.1.15 -
Worker
Inhalation
Central
Tendency
37
9 (>
4 291 :-()(
92S
( \PL 251
241
( \PL 25)
1 "IL-o"
( \LL 25)
Fabric, textile
and leather
(e.g., water repellant)
Fabric Finishing
8-hr TWA
High-
End
: i
() 5<>
9(,oi:-o5
53
( \PL 25)
14
( \PL25)
' S4I :-()(
( \LL 25)
products not
covered


Worker
Dermal
High-
End
4 "
(1 9 '
1 '0L-05
4"
(PI loi
9 ^
(PI 10)
2 (.11:-()(.
(LL 5)
elsewhere


ONU
Inhalation
Central
Tendency
37
9 (t
4 291 :-(>(,
\ A
\ A
\ A



8-hr TWA
High-
End
: i
1) 5(>
9(,oi:-o5
\ A
\ A
\ A
Industrial and
Function fluids for air conditioners:
Section 2.4.1.2.19


Central
5 1
1.'
' 1 IL-05
i:s

1 241 :-()(
commercial use/
refrigerant, treatment, leak sealer
and 4.3.2.1.14 -
Worker
Inhalation
Tendency
( \PL 25)
( \PL 25)
( \LL 25)
Automotive care
products

Miscellaneous Non-
Aerosol Industrial
8-hr TWA
High-
End
u 'i
DOS
(. 5SL-04
l(.
( \PI 50)
4o
( ALL 50)
2 (.'L-05
( \LL 25)


and Commercial Uses
Worker
Dermal
High-
End
4.<>
0 90
1 '5L-05
4(>
(PL loi
9 0
(PL 10)
2 "o| :-()(
(LL 5)



ONU
Inhalation
Central
Tendency
5 1
1. '
' 1 IL-05
\ A
\ A
\ A



8-hr TWA
High-
End
u '1
DOS
(. 5SL-04
\ \
\ A
\ \

Interior car care - spot remover
Section 2.4.1.2.8 and
4.3.2.1.10 -
Worker
Inhalation
Central
Tendency
48
12
3.31E-06
1201
(APF 25)
312
(APF 25)
1.32E-07


Commercial Aerosol
Products (Aerosol
8-hr TWA
High-
End
1 '
0 V,
1 (. 11-04
32
(APF 25)
17
(APF 50)
6.44E-06
Page 325 of 753

-------
l.ilc (>ele
Siaue ( aleuors
Siihcaleuor\
()cciipalional
1 Aposnre Scenario
Degreasing, Aerosol
Lubricants,
Automotive Care
Products)
Population
1 Aposlll'C
koine and
1 Juration
1 Aposlll'C
l.e\el
Risk 1 Siimales lor \o I'M!
Risk 1 !siiniales w illi PPI
\cnie
Non-
cancer
(bench-
mark
\ioi:
'i)i
(limine
Noil-
cancer
(bench-
mark
\ioi:
10)
( a i icer
(he lie li-
ma rk
l<> i
\enle
Nun-
eaneer
(he lie li-
ma rk
\ioi:
'())
( limine
Nini-
eaneer
(he lie li-
ma rk
\ioi:
10)
Cancer
(bench-
mark
10 1
Worker
Dermal
High-
End
4.6
o.<>
1 '5E-05
4o
(PF 10)
9.0
(PF 10)
2.70E-0O
(PF5)
ONU
Inhalation
8-hr TWA
Central
Tendency
4X
i:
' ^ 11 -()(.
N A
N \
N A
High-
End
1.'
(1 V,
i11 :-(>4
N A
N \
N A
Degreasers: gasket remover, transmission
cleaners, carburetor cleaner, brake
quieter/cleaner
Section 2.4.1.2.8 and
4.3.2.1.10-
Commercial Aerosol
Products (Aerosol
Degreasing, Aerosol
Lubricants,
Automotive Care
Products)
Worker
Inhalation
8-hr TWA
Central
Tendency
48
12
3.31E-06
1201
(APF 25)
312
(APF 25)
1.32E-07
High-
End
1 '
(i v,
1 (. 11-04
'2
( \PP 251
r
( \PI" 5o i
(, 441;_()(,
Worker
Dermal
High-
End
4 (>
0 'J
1 '51: -() 5
4<>
(PI KM
0
(PI' loi
: "in :-()<
( pi .*>
ONU
Inhalation
8-hr TWA
Central
Tendency
4X
i:
' 'li:-(K.
N \
N \
N \
High-
End
1 '
(i v,
1 (. 11-04
N \
N \
N \
Industrial and
commercial use/
Apparel and
footwear care
products
Post-market waxes and polishes applied
to footwear (e.g., shoe polish)
Section 2.4.1.2.8 and
4.3.2.1.10 -
Commercial Aerosol
Products (Aerosol
Degreasing, Aerosol
Lubricants,
Automotive Care
Products)
Worker
Inhalation
8-hr TWA
Central
Tendency
48
12
' 'ii:-(K.
1201
(APF 25)
312
(APF 25)
1.32E-07
High-
End
1.'
(1 V,
i11 :-o4
32
( \PP 251
17
( \PI 5oi
6 44E-06
Worker
Dermal
High-
End
4.<>
().'>
1 '51: -o 5
4<>
(PI KM
'J o
(PI KM
: "in :-()<
(PI" 5i
ONU
Inhalation
8-hr TWA
Central
Tendency
4X
i:
' 'ii:-(K.
N A
N \
N A
High-
End
1.'
(i v,
i11 :-o4
N A
N \
N A
Industrial and
commercial use/
Laundry and
dishwashing
products
Spot remover for apparel and textiles
Section 2.4.1.2.13
and 4.3.2.1.16 - Spot
Cleaning
Worker
Inhalation
8-hr TWA
Central
Tendency
436
113
3.66E-07
10896
(APF 25)
2830
(APF 25)
1.4t>E-08
(APF 25)
High-
End
1 (.
1)41
I.'li:-(i4
39
(APF 25)
10
(APF 25)
5.25E-06
(APF 25)
Worker
Dermal
High-
End
4 ')
o y
i :<.i:-o5
4Q
(PI KM
9.7
(PI loi
2 51E-06
(PI 51
ONU
Inhalation
8-hr TWA
Central
Tendency
436
113
3.66E-07
N \
N \
N \
Page 326 of 753

-------






Risk 1 Simmies lor \o I'M!
Risk 1 !s|iinalcs w illi I'I'I
l.ilc (>clc
Siauc ( ;ileuni'\
SuhcnlcuoiA
()ccupnlKninl
1 ApoMirc Scenario
Population
1 ApoMiie
kouic and
1 Juration
1 Aposurc
l.e\el
\euie
\ou-
c; nicer
(bench-
mark
\ioi:
'i)i
Chronic
\on-
canccr
(hcncli-
mark
\ioi:
10)
Cancer
i he nc li-
ma rk
l<> i
\culc
\on-
canccr
i he nc li-
ma rk
\ioi:
'0)
( limine
\ou-
caiiccr
i he lie li-
ma rk
\ioi:
10)
Cancer
(bench-
mark
10 )





1 liuli-
1 lid
1 (.
i).4
1 -11 -1)4
\ A
\ A
\ A
Industrial and
commercial use/
Liquid and spray lubricants and greases
Section 2.4.1.2.8 and
4.3.2.1.10-
Worker
Inhalation
Central
Tendency
48
12
3.31E-06
1201
(APF 25)
312
(APF 25)
1.32E-07
Lubricants and
greases

Commercial Aerosol
Products (Aerosol
8-hr TWA
High-
End
1.'
(i V,
i11 :-(>4
'2
( \PP 251
r
( \PI' 50)
(.441 :-()(


Degreasing, Aerosol
Lubricants,
Worker
Dermal
High-
End
4 (>
0 'J
i '5i:-()5
4<>
(PI 10)
0
( PI ' 10)
: "oi:-()(.
( pi -s)


Automotive Care
Products)
ONU
Inhalation
Central
Tendency
4X
i:
' ' 11 :-(>(>
\ \
\ A
\ \



8-hr TWA
High-
End
1 '
(i v,
1 (. 11 -<)4
\ \
\ A
\ \


Section 2.4.1.2.19
and 4.3.2.1.14 -
Worker
Inhalation
Central
Tendency
5 1
i '
' 1 1 E-05
128
( \PP 25)
33
( \PI 25)
1.24E-06
( \PI 25)


Miscellaneous Non-
Aerosol
8-hr TWA
High-
End
u '1
mis
(. 5S|-:-04
l(.
(API 50)
4.0
( API'50)
2 <.'L-()5
( \PI 25)


Industrial and
Commercial Uses
Worker
Dermal
High-
End
"1
(i <>(>
1 '5L-05
4<>
(PI 10)
'HI
(PI Id)
: "oi:-()(.
( pi -s)



ONU
Inhalation
Central
Tendency
5 1
1.'
' 1 IL-05
\ A
\ A
\ A



8-hr TWA
High-
End
u '1
DOS
(. 5SL-04
\ A
\ A
\ A

Degreasers - aerosol and non-aerosol
degreasers and cleaners
Section 2.4.1.2.8 and
4.3.2.1.10 -
Worker
Inhalation
Central
Tendency
4X
i:
' ' 1 r-oo
1201
(APF 25)
312
(APF 25)
1.32E-07


Commercial Aerosol
Products (Aerosol
8-hr TWA
High-
End
1.'
(i v,
i11 :-o4
32
( \PP 25)
17
( \PI' 50)
<-, 44r-of,


Degreasing, Aerosol
Lubricants,
Worker
Dermal
High-
End
4.<>
o.i>
1 '5L-05
4<>
(PI 10)
'J o
(PI 10)
: "oi :-o(.
(PI" 5)


Automotive Care
Products)
ONU
Inhalation
Central
Tendency
4S
i:
' 'li:-0(,
\ \
\ A
\ \



8-hr TWA
High-
End
1 '
(i v,
1 (. 11-04
\ \
\ A
\ \


Section 2.4.1.2.19
and 4.3.2.1.14 -
Worker
Inhalation
8-hr TWA
Central
Tendency
5 1
i '
'III :-05
128
(APF 25)
33
(APF 25)
1.24E-UO
(APF 25)
Page 327 of 753

-------






Risk 1 :siimales for \o I'M!
Risk 1 !siiniales w nli PPI!
l.ilc (>ele
Siaue ( aleuors
Siihcaleuor\
()ccupalioual
1 Aposure Scenario
Population
1 Aposure
kouie and
1 )iiralK 5SI :-(i4
l<>
( \IJI 50)
4o
(API 50)
2 <-1 :-o5
( \PL251


and ( oniniercial I ses
Worker
Dermal
Midl-
and
4.(>
()<)()
1 -51 -05
4(>
(PI 10)
').(!
( PI' 10)
2 "in :-((.
(PL 51



<>\l
Inhalation
( euiral
Tcudeucs
5 1
1.'
^ 1 IL-II5
\ A
\ A
\ A



S-hrTW \
Midl-
and
u -1
(MIS
(, 5xL-()4
\ \
\ A
\ \
Industrial and
commercial use/
Cold pipe insulation
Section 2.4.1.2.8 and
4.3.2.1.10 -
Worker
Inhalation
Central
Tendency
4S
i:
' -11 -IK.
1201
(APF 25)
'i:
(APF 25)
1 -2L-07
Building/
construction

Commercial Aerosol
Products (Aerosol
8-hr TWA
High-
End
1 -
(i v,
1 (. 11-04
32
(APF 25)
17
(APF 50)
6.44E-06
materials not
covered

Degreasing, Aerosol
Lubricants,
Worker
Dermal
High-
End
4 (>
(i')
1 '5E-05
46
(PI loi
9.0
(PL loi
2.70E-06
(PL 51
elsewhere

Automotive Care
Products)
ONU
Inhalation
Central
Tendency
4X
i:
' -11 :-o(.
\ \
\ A
\ \



8-hr TWA
High-
End
1.'
(i v,
i11 :-o4
\ A
\ A
\ A
Industrial and
commercial use/
All other chemical product and
preparation manufacturing
Section 2.4.1.2.3 and
4.3.2.1.4 - Processing
Worker
Inhalation
Central
Tendency
:
(i "4
5 5SL-05
143
( \PI" 5oi
37
( \PL5oi
2.23E-06
( \PL251
Solvents (which
become part of

- Incorporation into
Formulation, Mixture,
8-hr TWA
High-
End
1)54
(1.14
^ SIL-II4
2"
( \PI 50)
"0
( \PL50i
1 52L-05
( \PL251
product
formulation or
mixture)

or Reaction Product
Worker
Inhalation
15-min
TWA*
Point
Estimate
5
\ (
\ (
( \PI 251
\ (
\ (



Worker
Dermal
High-
End
"1
1.4
si.'^i :-(K.
-5<>
(PL 51
:s
(PL :oi
i "4i :-(K.
(PL 51



ONU
Inhalation
15-min
TWA*
Point
Estimate
2
(i "4
5 5 S1: -(15
\ \
\ A
\ \



ONU
Inhalation
Central
Tendency
(154
(i 14
^ SIL-II4
\ \
\ A
\ \



8-hr TWA
High-
End
5
\ (
\ (
\ \
\ A
\ \
Page 328 of 753

-------






Risk 1 :siimales for \o I'M!
Risk 1 !s|iniales u nh PPI!
l.ilc (>ele
Siaue ( aleuors
Suhcaleuor\
()ccupalioual
1 Aposure Scenario
Population
1 Aposure
Route and
1 )uraliou
1 Aposure
I.CNCl
\cuie
Nou-
caucer
(bench-
mark
\I()L
-n i
(limine
Noil-
cancer
(bench-
mark
\I()L
Kii
( a i icer
(he iieh-
mark
Hi i
\eule
\on-
eaueer
(he iieh-
mark
\I()L
-0)
( limine
\ou-
eaueer
(he iieh-
mark
\I()L
ID)
Cancer
(bench-
mark
10 1
ludiisirial and
commercial use
In multiple iiiauiil'acliiriim sectors
Secliou : 4 1 : 14
and 4-21 r -
Worker
lulialalioii
Central
Teudeiicv
0.28
(i.(i~
5 < >81!-(>4
14
( \IJI 50)
i (
( \IJI 50)
2 2"I:-(15
( \PI 251
Processiim aid
no L otherwise

Cellulose Triacelale
Film Production
8-hr'l'W \
1 hull-
End
H.2I
(i.(i5
"(."L-i)4
Hi
( \IJI 50)
"> -
( \IJI 50)
i o"i :-o5
( \PI 251
listed


Worker
Dermal
High-
End
"1
1.4
8 (i'ji :-()(.
1(1
(PL 5)
28
(PI 20)
i "4i :-o(.
(pf 5)



ONU
Inhalation
Central
Tendency
(1 28
oir
5 (.8i :-( 14
\ \
\ \
\ \



8-hr TWA
High-
End
U2I
005
- (,-| ;_(i4
\ \
\ \
\ \
Industrial and
commercial use/
Flexible polyurethane foam
manufacturing
Section 2.4.1.2.15
and 4.3.2.1.19 -
Worker
Inhalation
Central
Tendency
1 5
0
i u.i:-()4
-X
( \PI' 25)
20
( \\'\: 50)
4 (>(>l !-()(>
( \PI 25)
Propellants and
blowing agents

Flexible Polyurethane
Foam Manufacturing
8-hr TWA
High-
End
(i 2<>
DOS
- o8i :-(>4
15
( \IJI 50)
- 8
( \PI 50)
2 8 i|:-()5
( \PI 25)



Worker
Dermal
High-
End
" 1
1 4
8 (.'>i :-o(.
-5(>
(PI' 5)
28
(PI 20)
1 "41 :-()(
(PL 5)



ONU
Inhalation
Central
Tendency
1 5
0 v;
Li(.i:-u4
\ A
\ \
\ A



8-hr TWA
High-
End
(>.:>
(1.(18
"(I8L-04
\ A
\ \
\ A
Industrial and
commercial use/
Laboratory chemicals - all other chemical
product and preparation manufacturing
Section 2.4.1.2.16
and 4.3.2.1.20 -
Worker
Inhalation
Central
Tendency
48
12
- -11:-()(.
208"
( \PI' 25)
' 12
( \PI 25)
i -2i :-o"
( \PI 25)
Other Uses

Laboratory Use
8-hr TWA
High-
End
2 8
I) "4
" 2IL-05
""
( \PI' 25)
18
( \PI 25)
2 8<>l:-()(.
( \PI 25)



Worker
Inhalation
15-min
TWA*
Central
Tendency
25(>
\ (
\ (
(.VJ4
( \PI' 25)
\ (
\ (



High-
End
22
\ (
\ (
54<>
( \PI' 25)
\ (
\ (



Worker
Dermal
High-
End
4 (>
()')
1 ^51 -05
1
(PI 20)
18
(PI' 20)
2 "oi :-o(.
(pf 5)



ONU
Inhalation
Central
Tendency
48
12
- -11:-()(.
\ \
\ \
\ \



8-hr TWA
High-
End
2 8
() "4
" 2 11-0 5
\ \
\ \
\ \
Page 329 of 753

-------






Risk 1 Snniales for \o I'M!
Risk 1 \uniales w illi I'I'I
l.ilc (>ele
Siaue ( aleuors
Suhcalcuor\
()eeupalK\l
Inhalation
Central
Tcudeucs
:5(.
\ (
\ (
N/A
\ (
\ (



1 5-iiiim
T\V \ *
1 liuli-
1 ikI
> >
\ (
\ (
N/A
\ (
\ (

Llecirical equipment. ;ippli;inee. and
component niaiiiifacliirum
Section 2 4 1 2 ll>
and 4 ' 2 1 14 -
Worker
Inhalation
Central
Tcudeucs
5 1
1 v.
'III!-(>5
128
( \PP 25)
( \PI" 25)
1241 :-0(>
( \PI 25)


Miscellaneous \ou-
\erosol Indiisiiial
X-hrTW \
1 liuli-
1 ikI
u '1
(MIS
(, 5xL-i>4
16
( \IJI 5(ii
4.(1
(API 5(H
2 (.'L-o5
( \PI 25)


and ('oniniercial I ses
Worker
Dermal
1 liuli-
1 ikI
4 (>
(1 'J( 1
1 '5L-05
46
(PI KM
0
(PI' Id)
2 "in :-(K.
(pf 5)



<>\l
Inhalation
(eniral
1 cudeucs
5 1
1. "
'III!-(>5
N/A
\ \
\ \



X-hrTW \
1 liuli-
Lnd
u '1
(MIS
(, 5xL-i>4
N/A
\ \
\ \

Plastic and rubber products
Section 2.4.1.2.17
and 4.3.2.1.18 -
Worker
Inhalation
Central
Tendency
U
X 'J
4 (.(.1 :-(>(,
853
( \PP 25)
221
( \PI" 25)
i s'L-o"
( \PI 25)


Plastic Product
Manufacturing
8-hr TWA
High-
End
1.4
II
1 4(.| -04
30
(APF 25)
18
(APF 50)
5.83E-06
(APF 25)



Worker
Inhalation
15-min
TWA*
Central
Tendency
21
\ (
\ (
517
(APF 25)
\ (
\ (



High-
End
1 '
\ (
\ (
328
(APF 251
\ (
\ (



Worker
Dermal
High-
End
"1
1.4
x<.<>i :-(K.
36
(PL 51
2X
(PI 2d)
i ~4i :-(>(.
(pf 5)



ONU
Inhalation
Central
Tendency

7.3
5 'IL-IK.
N/A
\ \
\ \



8-hr TWA
High-
End
2x
" S
" 2si :-(K.
N/A
\ \
\ \


Section 2.4.1.2.14
and 4.3.2.1.17 -
Worker
Inhalation
Central
Tendency
u.:s
(Mi-
5 (.si :-04
14
( \IJI 5(>i
' (.
( \PI 50)
2 2"L-o5
( \PI 25)


Cellulose Triacetate
Film Production
8-hr TWA
High-
End
11.21
ni )5
"(."L-H4
10
( \IJI 5(1)
2 "
( \PI 50)
' o"L-o5
( \PI 25)



Worker
Dermal
High-
End
" 1
1 4
x<.<>i :-(K.
36
(PL 51
2S
(PI' 20)
1 "41 :-()<
(PL 5)
Page 330 of 753

-------






Risk 1 Snniales lor No I'M :
Risk 1 !siinialcs w illi PPI
l.ilc (>clc
Siauc ( alcuors
Siihcalcuois
()cciipalional
1 Aposiiic Scenario
Population
1 ApoMiie
konic and
1 Juration
1 Aposiiic
l.e\el
\cnic
\on-
c; nicer
(bench-
mark
\I()L
'i)i
( limine
Nun-
cm ice i"
(bench-
mark
\I()L
ID)
( a i icc r
i he nc li-
ma i'k
|0 )
\cnic
Non-
c; nicer
(he nc li-
ma ik
\I()L
'0)
( limine
Non-
caiicer
(he nc li-
ma rk
\I()L
10)
Cancer
(bench-
mark
10 )



<>\l
Inhalation
( aural
Tendeiicv
o.2S
0.0"
5 ('XI :-04
\ A
\ A
\ A



X-hiTW \
1 Imh-
End
u.21
o.o5
"(."L-04
\ A
\ A
\ A

Anti-adhesive agent - anti-spatter
welding aerosol
Section 2.4.1.2.8 and
4.3.2.1.10 -
Worker
Inhalation
Central
Tendency
4X
i:
3.31E-06
1201
(APF 25)
312
(APF 25)
1.32E-07


Commercial Aerosol
Products (Aerosol
8-hr TWA
High-
End
1 '
0 V,
1 (. 11-04
'2
( \PL 251
r
( \PI" 50)
(.441 :-()(


Degreasing,
Aerosol Lubricants,
Worker
Dermal
High-
End
4 (>
0 'J
1 '5L-05
4(>
(PI 10)
0
( PI ' 10)
2 ~oi :-(>(.
(PL 5)


Automotive Care
Products)
ONU
Inhalation
Central
Tendency
4X
i:
' 'IL-0(,
\ \
\ A
\ \



8-hr TWA
High-
End
1 '
0 V,
1 (. 11-04
\ \
\ A
\ \

Oil and gas drilling, extraction, and
support activities
Section 2.4.1.2.19
and 4.3.2.1.14 -
Worker
Inhalation
Central
Tendency
5 1
1 '
' 1 IL-05
i:x
( \PL 25)
33
( \PL25)
1241 -in.
( \PL25)


Miscellaneous Non-
Aerosol Industrial
8-hr TWA
High-
End
u '1
DOS
(. 5XL-04
l(>
( \IJI 50)
4o
( API'50)
2 (.'L-05
( \PL25)


and Commercial Uses
Worker
Dermal
High-
End
4.<>
0 <>()
1 '5L-05
4(>
(PI 10)
'HI
(PL 10)
2 "()| :-()<
(PL 5)



ONU
Inhalation
Central
Tendency
5 1
1.'
' 1 IL-05
\ A
\ A
\ A



8-hr TWA
High-
End
u '1
(MIX
(. 5XL-04
\ A
\ A
\ A

Toys, playground, and sporting
equipment - including novelty articles
Section 2.4.1.2.19
and 4.3.2.1.14 -
Worker
Inhalation
Central
Tendency
5 1
1.'
' 1 IL-05
i:x
( \PI 25)
( \PL25)
1 241 :-()<
( \PL25)

(toys, gifts, etc.)
Miscellaneous Non-
Aerosol Industrial
8-hr TWA
High-
End
u '1
O.OS
(. 5XL-04
l(.
( \PI 50)
4o
(API 50)
2 (.'L-05
( \PL25)


and Commercial Uses
Worker
Dermal
High-
End
4 (>
0 'JO
1 '5L-05
4<>
(PI 10)
') o
(PL 10)
2 "()| :-()<
(PL 5)



ONU
Inhalation
Central
Tendency
5 1
1 '
' 1 IL-05
\ \
\ A
\ \



8-hr TWA
High-
End
u '1
0 ox
(. 5XL-04
\ \
\ A
\ \
Page 331 of 753

-------
l.ilc (>ele
Siaue ( aleuors
Siihcaleuor\
()eeiipalK i
\eule
Noil-
cancer
(he iieh-
mark
\I()L
'()>
( limine
\oii-
eaiieer
(he iieh-
mark
\I()L
10)
Cancer
(bench-
mark
10 )
Lithographic
printing cleaner
Section 2.4.1.2.18
and 4.3.2.1.22 -
Lithographic Printing
Plate Cleaning
Worker
Inhalation
8-hr TWA
Central
Tendency
33
S "
4 "SE-06
832
(APF 25)
216
(APF 25)
1.91E-07
(APF 25)
High-
End
1 S
0.4"
i.ni:-t)4
45
( \PL 5oi
12
( \PL 251
4 541 :-()(
( \PL25)
Worker
Dermal
High-
End
5 1
1 o
1 2 11 -05
5 1
(PI loi
lo
(PL loi
2 411 :-()(
(LI
ONU
Inhalation
8-hr TWA
Central
Tendency
33
8 "
4 "SI:-()(.
\ \
\ \
\ \
High-
End
1 S
i)4"
1 1 -1-04
\ \
\ \
\ \
Carbon remover, Wood floor cleaner, and
Brush cleaner
Section 2.4.1.2.19
and 4.3.2.1.14 -
Miscellaneous Non-
Aerosol Industrial
and Commercial Uses
Worker
Inhalation
8-hr TWA
Central
Tendency
5 1
1. -
- 1 IL-05
i:s
( \PL 25)
( \PL 251
1241 :-o(.
( \PL 25)
High-
End
u '1
DOS
(. 5SL-04
l(.
( \IJI 5oi
4.0
(ALL 5oi
2 ('1:-()5
( \PL 25)
Worker
Dermal
High-
End
4 (>
ii <;<>
1 '5L-05
4<>
(PI loi
0
(PL loi
2 "oi :-o(.
(PI 5)
ONU
Inhalation
8-hr TWA
Central
Tendency
5 1
1 v.
- 1 IL-05
\ A
\ \
\ A
High-
End
u '1
DOS
(. 5SL-04
\ A
\ \
\ A
Disposal/
Disposal
Industrial pre-treatment
Industrial wastewater treatment
Section 2.4.1.2.20
and 4.3.2.1.6 - Waste
Handling, Disposal,
Treatment, and
Recycling
Worker
Inhalation
8-hr TWA
Central
Tendency
124
'2
i :>)i :-o(.
;(><>:
( \PI 25)
SO'
( \PL25)

Publicly owned treatment works (POTW)
Underground injection
High-
End
' (.
ii
5 "IL-05
<>(>
( \PI 25)
2 '
( \PL 25)

Municipal landfill
Hazardous landfill
Worker
Dermal
High-
End
"1
1.4
S(.')i :-o(.
-5(>
(PL 51
2S
(PI 20)
i "4i :-(>(.
(PL 5)
Other land disposal
Municipal waste incinerator
ONU
Inhalation
8-hr TWA
Central
Tendency
124
'2
1.29E-06
N/A
\ \
\ A
Off-site waste transfer
High-
End
' (.
(IT.
5.71E-05
\ \
\ \
\ \
N/C = not calculated because 15-min TWAs are not used for assessing chronic non-cancer or cancer risks
* risk estimates for the 15-min TWA are shown for COUs that had available exposure data and when risks from acute exposure indicated were different from 8-hr TWA, see
Section 4.2.2.1 for details of 15-min TWAs for each OES. N/A = not assessed because ONUs are not assumed to be wearing PPE
- = cancer risks assuming PPE are not shown when the cancer risk without PPE was above the cancer risk benchmark of 10~4
Page 332 of 753

-------
4.1.3 Summary of Risk Estimates for Inhalation and Dermal Exposures to
Consumers and Bystanders
Table 4-3 summarizes the risk estimates for CNS effects from acute inhalation and dermal
exposures for all consumer exposure scenarios. Risk estimates that exceed the benchmark (i.e.,
MOEs less than the benchmark MOE) are highlighted by bolding the number and shading the
cell. The risk characterization is described in more detail in Sections 2.4.2 and 4.3.2.3 and
specific links to the exposure and risk characterization sections are listed in Table 4-3 in the
column headed Consumer Condition of Use Scenario.
Page 333 of 753

-------
Table 4-3 Summary of Risk Estimates for CNS effects from Acute Inhalation and Dermal Exposures to Consumers by
Conditions of Use


CdIISIIIIHT
Cnmlilinn of
I so Scen.irio


i scr moi:
(bench in ;uk
moi-: = jo)
IS\sl;imkT
Ciileiion
Siih Csiicgon
Kxposmv Kouli*
iiml Dumlion
SiTiisirio Description
MOI.
(honchiiiiirk




MOI.=30)




Low Intensity User
24
:o:



Inhalation 1-hr
Medium Intensity User
1 "
14




High Intensity User
ii4'
: '


Section 2.4.2.4.5
and Section
4 3 2 3 1 - Brake

Low Intensity User
5"
:is


Inhalation 8-hr
Medium Intensity User
' (.
15


Cleaner

High Intensity User
o 5c
: u




Low Intensity User

\ \



Dermal
Medium Intensity User
44
\ \




High Intensity User
() '2
\ \




Low Intensity User

\ \




High Intensity User

\ \




Low Intensity User
1'
1 lu


Section 2.4.2.4.8
Inhalation 1-hr
Medium Intensity User
1 4
i:


and Section
4.3.2.3.3 -
Carburetor

High Intensity User
0 M)
2 I)



Low Intensity User
:~
1 IS


Cleaner
Inhalation 8-hr
Medium Intensity User
vll
i'




High Intensity User
u.55
: i)
Page 334 of 753

-------


Consumer
Cnmlilinn of
I so Scon.irio


i scr moi:
(bench in ;uk
moi-: = jo)
|}\s(;ni(kr
Ciileiion
Siih Csiicgon
Mxposiiiv Kniilc
iiml Diimlinn
SiTiiiirio Dcscriplion
MOI.
(honchiiiiirk




MOI.=30)




Low Intensity User
158
N/A



Dermal
Medium Intensity User
lu
N/A




High Intensity User
l.o
N/A




Low Intensity User
5 5
60



Inhalation 1-hr
Medium Intensity User
u 5~
5 'J




High Intensity User
o 1 1
() (.1


Section 2.4.2.4.9

Low Intensity User
1 ^
(,')


and Section
4.3.2.3.4 - Coil
Cleaner
Inhalation 8-hr
Medium Intensity User
1 ^
<..x



High Intensity User
u 14
11.5"




Low Intensity User
::
\ \



Dermal
Medium Intensity User
IS
\ \




High Intensity User
u::
\ \




Low Intensity User
1171
8027



Inhalation 1-hr
Medium Intensity User
91
633


Section
2.4.2.4.11 and

High Intensity User
(> 5
31



Low Intensity User
2492
10794


Section 4.3.2.3.5
Inhalation 8-hr
Medium Intensity User
195
854


- Electronics
Cleaner

High Intensity User
1 ^
46



Low Intensity User
1208
N/A



Dermal
Medium Intensity User
328
N/A




High Intensity User
64
N/A




Low Intensity User
5 4
4n


Section
Inhalation 1-hr
Medium Intensity User
o (:
5 1


2.4.2.4.12 and
Section 4.3.2.3.6
- Engine Cleaner

High Intensity User
() l(.
() SS


Inhalation 8-hr
Low Intensity User
i:
5(1



Medium Intensity User
I.'
5 4
Page 335 of 753

-------
Ciileiion
Siih Csiicgon
Consumer
Cnmlilinn of
I so Scen.irio
Kxposmv Roule
iiml Diimlion
Scciiiirio Description
I sir MOI.
(bench in ;uk
moi-: = jo)
litshimlcr
MOI.
(I>cnchm;irk
MOI.=30)




High Intensit\ L scr
(i::
0
Dermal
Low Intensity User

\ \
Medium Intensity User
4.7
\ \
High Intensity User
() .X
\ \
Section
2.4.2.4.13 and
Section 4.3.2.3.7
- Gasket
Remover
Inhalation 1-hr
Low Intensity User
5
51
Medium Intensity User
I.I
1
High Intensity User
it::
1 4
Inhalation 8-hr
Low Intensity User
i ^
55
Medium Intensity User
2 ^
"
High Intensity User
0 4:
1 4
Dermal
Low Intensity User

\ \
Medium Intensity User
2V
N/A
High Intensity User
(1 "2
N/A
Adhesives and Sealants
Single component
glues and adhesives
and sealants and caulk
Section 2.4.2.4.1
and Section
4.3.2.3.8-
Adhesives
Inhalation 1-hr
Low Intensity User
I'M
2188
Medium Intensity User
12
1
High Intensity User
I) 5'
42
Inhalation 8-hr
Low Intensity User
452
2535
Medium Intensity User
27
I5U
High Intensity User
1 1
4."
Dermal
Low Intensity User

\ \
Medium Intensity User
i -
N/A
High Intensity User
( i
V\
Section
2.4.2.4.14 and
Section
4.3.2.3.14 -
Sealant
Inhalation 1-hr
Low Intensity User
35
-<)4
Medium Intensity User
:
24
High Intensity User
o 5'J
- S
Inhalation 8-hr
Low Intensity User
75
327
Page 336 of 753

-------
Ciileiion
Siih Csiicgon
Cdiisiiiiht
Cnmlilinn of
I so Scen.irio
Kxposmv Kouli*
iiml Dumlion
SiTiisirio Description
i scr moi:
(bench in ;uk
moi-: = jo)
litshimliT
MOI.
(honchiiiiirk
MOI.=30)




Medium Intensi I \ I ser
(. i
2(>
High Intensit\ I scr
i i
i (t
Dermal
Low Intensity User
198
N/A
Medium Intensity User
l(.
N/A
High Intensity User
12
N/A
Paints and coatings including paint and
coating removers
Paint and Coating
Removers
Section 2.4.2.4.6
and Section
4.3.2.3.10 -
Brush Cleaner
Inhalation 1-hr
Low Intensity User
3956
44077
Medium Intensity User
786
6209
High Intensity User
462
1293
Inhalation 8-hr
Low Intensity User
8981
50216
Medium Intensity User
1653
6916
High Intensity User
191
919
Dermal
Low Intensity User
396
N/A
Medium Intensity User
33
N/A
High Intensity User
4 "
\ \
Adhesive/caulk
removers
Section 2.4.2.4.2
and Section
4.3.2.3.11 -
Adhesives
Remover
Inhalation 1-hr
Low Intensity User
255

Medium Intensity User
r
1 u
High Intensity User
1 1
14
Inhalation 8-hr
Low Intensity User
581
3269
Medium Intensity User
36
150
High Intensity User
4 ^
l(.
Dermal
Low Intensity User
:i
\ \
Medium Intensity User
u.-|
N/A
High Intensity User
OO'JO
N/A
Metal products not covered elsewhere
Degreasers - aerosol
and non-aerosol
degreasers
Section 2.4.2.4.7
and Section
4.3.2.3.2-
Carbon Remover
Inhalation 1-hr
Low Intensity User
l> 5
103
Medium Intensity User
0 
-------


Consumer
Cnmlilinn of
I so Scon.irio


i scr moi:
(bench in ;uk
moi-: = jo)
IS\sl;imkT
Ciileiion
Siih Csiicgon
Mxposiiiv Kniilc
iiml Diimlinn
SiTiiiirio Dcscriplion
MOI.
(honchiiiiirk




MOI.=30)




Low Intensity User

119



Inhalation 8-hr
Medium Intensity User
: i
1 1




High Intensity User
o 2 '
n.Vi




Low Intensity User

N/A



Dermal
Medium Intensity User
>
N/A




High Intensity User
0 ^(.
N/A




Low Intensity User
5.5
(.0



Inhalation 1-hr
Medium Intensity User
u 5"
5 'J




High Intensity User
I) 1 1
() (.1


Section 2.4.2.4.9

Low Intensity User
1 ^
(,')


and Section
4.3.2.3.4 - Coil
Cleaner
Inhalation 8-hr
Medium Intensity User
1 ^
(. S



High Intensity User
u 14
u 5"




Low Intensity User

N/A



Dermal
Medium Intensity User
1 S
N/A




High Intensity User
u::
N/A




Low Intensity User
1171
8027



Inhalation 1-hr
Medium Intensity User
91
633


Section
2.4.2.4.11 and

High Intensity User
(> 5
31



Low Intensity User
2492
10794


Section 4.3.2.3.5
Inhalation 8-hr
Medium Intensity User
195
854


- Electronics
Cleaner

High Intensity User
1 ^
46



Low Intensity User
1208
N/A



Dermal
Medium Intensity User
328
N/A




High Intensity User
64
N/A
Page 338 of 753

-------
Ciileiion
Siih Csiicgon
CdIISIIIIHT
Cnmlilinn of
I so Scen.irio
Kxposmv Kouli*
iiml Dumlion
SiTiiiirio IK'scriplion
i scr moi:
(bench in ;uk
moi-: = jo)
litshimliT
MOI.
(honchiiiiirk
MOI.=30)
Automotive care products
Function fluids for air
conditioners:
refrigerant, treatment,
leak sealer
Section 2.4.2.4.3
and Section
4.3.2.3.9-
Automotive AC
Leak Sealer
Inhalation 1-hr
Low Intensity User
120
1031
Medium Intensity User
123
1015
High Intensity User
210
1117
Inhalation 8-hr
Low Intensity User
255
1107
Medium Intensity User
259
1077
High Intensity User
:_4
980
Dermal
Low Intensity User
III
N/A
Medium Intensity User
5.0
N/A
High Intensity User
" 'J
N/A
Section 2.4.2.4.4
and Section
4.3.2.3.12 -
Automotive AC
Refrigerant
Inhalation 1-hr
Low Intensity User
i<>:
875
Medium Intensity User
x.x

High Intensity User
. (.
i'j
Inhalation 8-hr
Low Intensity User
:i(.
939
Medium Intensity User
IS
76
High Intensity User
4 "
r
Dermal
Low Intensity User
1482
N/A
Medium Intensity User
164
N/A
High Intensity User
:i
N/A
Degreasers: gasket
remover, transmission
cleaners, carburetor
cleaner, brake
quieter/cleaner
Section 2.4.2.4.5
and Section
4.3.2.3.1 - Brake
Cleaner
Inhalation 1-hr
Low Intensity User
24
:u:
Medium Intensity User
1."
14
High Intensity User
<> 4-
: ^
Inhalation 8-hr
Low Intensity User
5(1
:ix
Medium Intensity User
. (.
15
High Intensity User
o 5c
: u
Dermal
Low Intensity User
234
N/A
Medium Intensity User
44
N/A
Page 339 of 753

-------


Consumer
Cnmlilinn of
I so Scon.irio


i scr moi:
(bench in ;uk
moi-: = jo)
|}\s(;ni(kr
Ciileiion
Siih Csiicgon
Mxposiiiv Kniilc
iiml Diimlinn
SiTiiiirio Dcscriplion
MOI.
(honchiiiiirk




MOI.=30)




High Intensity User
o
\ \




Low Intensity User
n
llu



Inhalation 1-hr
Medium Intensity User
1 4
i:


Section 2.4.2.4.8
and Section

High Intensity User
I) 28
: u



Low Intensity User
:_
1 18


4.3.2.3.3 -
Inhalation 8-hr
Medium Intensity User
^ 0
n


Carburetor
Cleaner

High Intensity User
I) 55
: u



Low Intensity User
158
\ \



Dermal
Medium Intensity User
lu
\ \




High Intensity User
l.o
\ \




Low Intensity User
5.4
4"



Inhalation 1-hr
Medium Intensity User
I) (.0
5 1




High Intensity User
o 20
() 88


Section

Low Intensity User
i:
50


2.4.2.4.12 and
Section 4.3.2.3.6
- Engine Cleaner
Inhalation 8-hr
Medium Intensity User
1 ^
5 4



High Intensity User
o :<)
u ""




Low Intensity User

\ \



Dermal
Medium Intensity User
4 "
\ \




High Intensity User
1) .8
\ \




Low Intensity User
5.
-------
Ciileiion
Siih Csiicgon
Cdiisiiiiht
Cnmlilinn of
I so Scen.irio
Kxposmv Kouli*
iiml Dumlion
SiTiisirio Description
i scr moi:
(bench in ;uk
moi-: = jo)
litshimliT
MOI.
(honchiiiiirk
MOI.=30)




Medium Intensity User
: 'j
\ \
High Intensity User
u
\"\
Lubricants and greases
Degreasers - Aerosol
and non-aerosol
degreasers and
cleaners
Section 2.4.2.4.5
and Section
4.3.2.3.1 - Brake
Cleaner
Inhalation 1-hr
Low Intensity User
24
2()2
Medium Intensity User
i."
14
High Intensity User
ii 4^
2 ^
Inhalation 8-hr
Low Intensity User
5"
2 1S
Medium Intensity User
. (.
15
High Intensity User
o 5c
2.0
Dermal
Low Intensity User
234
XA
Medium Intensity User
44
\ \
High Intensity User
()
\ \
Section 2.4.2.4.8
and Section
4.3.2.3.3 -
Carburetor
Cleaner
Inhalation 1-hr
Low Intensity User
1 ^
1 lu
Medium Intensity User
1.4
12
High Intensity User
o :x
2 I)
Inhalation 8-hr
Low Intensity User
:_
1 IS
Medium Intensity User
^ 0
n
High Intensity User
u.55
2 u
Dermal
Low Intensity User
I5S
\ \
Medium Intensity User
lu
\ \
High Intensity User
l.o
\ \
Section
2.4.2.4.12 and
Section 4.3.2.3.6
- Engine Cleaner
Inhalation 1-hr
Low Intensity User
5.4
4"
Medium Intensity User
() <:
5 1
High Intensity User
() 1 c.
() SS
Inhalation 8-hr
Low Intensity User
12
50
Medium Intensity User
1 ^
5 4
High Intensity User
I) 22
u ""
Page 341 of 753

-------
Ciileiion
Siih Csiicgon
CdIISIIIIHT
Cnmlilinn of
I so Scen.irio
Kxposmv Kouli*
iiml Dumlion
SiTiisirio Description
i scr moi:
(bench in ;uk
moi-: = jo)
|}\s(;iii(kr
MOI.
(honchiiiiirk
MOI.=30)



Dermal
Low Intensity User
32
N/A
Medium Intensity User
4 "
N/A
High Intensity User
I) iX
N/A
Section
2.4.2.4.13 and
Section 4.3.2.3.7
- Gasket
Remover
Inhalation 1-hr
Low Intensity User
5
51
Medium Intensity User
1 1
1
High Intensity User
u 2:
1 4
Inhalation 8-hr
Low Intensity User
n
55
Medium Intensity User
2 ^

High Intensity User
11.42
1 4
Dermal
Low Intensity User
2
N/A
High Intensity User
u "2
V\
Building/ construction materials not
covered elsewhere
Cold pipe insulation
Section
2.4.2.4.10 and
Section
4.3.2.3.13 - Cold
Pipe Insulating
Spray
Inhalation 1-hr
Low Intensity User
i<>
l(."
Medium Intensity User
i (.
r
High Intensity User
() 28
2 2
Inhalation 8-hr
Low Intensity User
35
I'U
Medium Intensity User
. (.
2(1
High Intensity User
o
2 4
Dermal
Low Intensity User

N,A
Medium Intensity User
2d
N/A
High Intensity User
8 2
N/A
Arts, crafts, and hobby materials
Crafting glue and
cement/concrete
Section 2.4.2.4.1
and Section
4.3.2.3.8-
Adhesives
Inhalation 1-hr
Low Intensity User
I'W
2188
Medium Intensity User
12
1
High Intensity User
ii 5'
4 2
Inhalation 8-hr
Low Intensity User
452
2535
Medium Intensity User
2"
150
Page 342 of 753

-------
Ciileiion
Siih Csiicgon
Consumer
Cnmlilinn of
I so Scen.irio
Kxposmv Roule
iiml Diimlion
SiTiiiirio IK'scriplion
I sir MOI.
(bench m ;uk
moi-: = jo)
|}\s(;iii(kr
MOI.
(honchiiiiirk
MOI.=30)




High Intensit\ L ser
i.i
4 "
Dermal
Low Intensity User

\ \
Medium Intensity User
27
\ \
High Intensity User
(. .
\ \
Other Uses
Anti-adhesive agent -
anti-spatter welding
aerosol
Section
2.4.2.4.15 and
Section
4.3.2.3.15 - Weld
Spatter
Protectant
Inhalation 1-hr
Low Intensity User
4 (>
51
Medium Intensity User
o
lu
High Intensity User
() l<>
1 ^
Inhalation 8-hr
Low Intensity User
1 1
5<>
Medium Intensity User
2 1
i:
High Intensity User
u i5
1 5
Dermal
Low Intensity User
(>5
\ \
Medium Intensity User
8.2
N/A
High Intensity User

N/A
Brush Cleaner
Section 2.4.2.4.6
and Section
4.3.2.3.10 -
Brush Cleaner
Inhalation 1-hr
Low Intensity User
3956
44077
Medium Intensity User
786
6209
High Intensity User
462
1293
Inhalation 8-hr
Low Intensity User
8981
50216
Medium Intensity User
1653
6916
High Intensity User
191
919
Dermal
Low Intensity User
396
N/A
Medium Intensity User
33
N/A
High Intensity User
4 "
\ \
Carbon Remover
Section 2.4.2.4.7
and Section
4.3.2.3.2-
Carbon Remover
Inhalation 1-hr
Low Intensity User
'J 5
Hi'
Medium Intensity User
I) >J4
'i ~
High Intensity User
(i IS
1 n
Inhalation 8-hr
Low Intensity User

119
Page 343 of 753

-------


Consumer
Cnmlilinn of
I so Scon.irio


i scr moi:
(bench ni;irk
moi-: = jo)
|}\s(;iii(lcr
Ciileiion
Siih Csiicgon
Mxposiiiv Koulo
iind Diimlinn
Scciiiirio Description
MOI.
(honchiiiiirk




MOI.=30)




Medium Intensi I \ I ser
2 1
1 1




High Intensit\ I scr
o
() )?




Low Intensity User

N/A



Dermal
Medium Intensity User
:v
N/A




High Intensity User
0. "(i
N/A
Page 344 of 753

-------
4.2 Environmental Risk
EPA considered fate, exposure, and environmental hazard to characterize environmental risk of
methylene chloride. As stated in Section 2.1 Fate and Transport, methylene chloride is not
expected to bioconcentrate in biota or accumulate in wastewater biosolids, soil, sediment, or
biota. Releases of methylene chloride to the environment, are likely to volatilize to the
atmosphere, where it will slowly photooxidize. It may migrate to groundwater, where it will
slowly hydrolyze. Additionally, the bioconcentration potential of methylene chloride is low. EPA
modeled environmental exposure with surface water concentrations of methylene chloride
ranging from almost 0 to 18,100 ppb from facilities releasing the chemical to surface water.
Measured surface water concentrations in ambient water range from below the detection limit to
29 ppb. The modeled data represents estimated concentrations near facilities that are actively
releasing methylene chloride to surface water, while the reported measured concentrations
represent sampled ambient water concentrations of methylene chloride. Differences in magnitude
between modeled and measured concentrations may be due to measured concentrations not being
geographically or temporally close to known releasers of methylene chloride.
EPA concludes that methylene chloride poses a hazard to environmental aquatic receptors
(Section 3.1.5). Amphibians are the most sensitive taxa for both acute and chronic exposures. For
acute exposures, a hazard value of 26.3 mg/L was established for amphibians using data on
teratogenesis leading to lethality in frog embryos and larvae. For acute exposures, methylene
chloride also has toxicity values for fish as low as 99 mg/L and for freshwater aquatic
invertebrates as low as 135.8 mg/L. For chronic exposures, methylene chloride has a hazard
value for amphibians of 0.9 mg/L, based on teratogenesis and lethality in frog embryos and
larvae. For chronic exposures to fish, methylene chloride has hazard values as low as 1.5 mg/L.
For chronic exposure to aquatic invertebrates, methylene chloride has a toxicity value of 18
mg/L. In algal species, methylene chloride has toxicity values ranging from 33.1 mg/L to 242
mg/L (with the more sensitive value of 33.1 mg/L used to represent algal species as a whole).
A total of 14 acceptable aquatic environmental hazard studies were identified for methylene
chloride. EPA's evaluation of these studies was mostly high or medium during data quality
evaluation (see Table 3-1 in Section 3.1.2 and "Systematic Review Supplemental File: Data
Quality Evaluation of Environmental Hazard Studies CASRN: 75-09-2 "). The Methylene
Chloride (75-09-2) Systematic Review: Supplemental File for the TSCA Risk Evaluation
Document presents details of the data evaluations for each study, including scores for each
metric and the overall study score.
Given methylene chloride's conditions of use under TSCA outlined in problem formulation (U.S.
EPA. 2018c). EPA determined that environmental exposures are expected for aquatic species,
and risk estimation is discussed in Section 4.2.2.
4.2.1 Risk Estimation Approach
To assess environmental risk, EPA evaluates environmental hazard and exposure data. EPA used
modeled exposure data from E-FAST, as well as monitored data from the WQP
(www.waterqualitydata.iis). to characterize the exposure of methylene chloride to aquatic
Page 345 of 753

-------
species. Environmental risks are estimated by calculating a risk quotients (RQ). As stated
previously, modeled data was used to represent surface water concentrations near facilities
actively releasing methylene chloride to surface water, while the monitored concentrations were
used to represent ambient water concentrations of methylene chloride. RQs were calculated
using surface water concentrations and the COCs calculated in the hazard section of this
document (Section 3.1.4). The RQ is defined as:
RQ = Predicted Environmental Concentration / Effect Level or COC
RQs equal to 1 indicate that environmental exposures are the same as the COC. If the RQ is
above 1, the exposure is greater than the COC. If the RQ is below 1, the exposure is less than the
COC. The COCs for aquatic organisms shown in Table 3-2 and the environmental concentrations
described in Section 2.3.2 were used to calculate RQs (EPA. 1998).
EPA considered the biological relevance of the species that the COCs were based on when
integrating the COCs with the location of surface water concentration data to produce RQs. For
example, certain biological factors affect the potential for adverse effects in aquatic organisms.
Life-history and the habitat of aquatic organisms influences the likelihood of exposure in an
aquatic environment. In general, amphibian distribution is limited to freshwater environments.
More specifically, those amphibian (Rana sp.) species evaluated for hazards resulting from
chronic exposure (see Section 3.1.2) generally occupy shallow, vegetated, low-flow, freshwater
habitats. In contrast, fish generally occupy a much wider breadth of water body types and
habitats. If hazard benchmarks are exceeded by both amphibians and fish from estimated chronic
exposures, it provides evidence that the site-specific releases could affect that specific aquatic
environment.
Frequency and duration of exposure also affects potential for adverse effects in aquatic
organisms. Therefore, the number of days that a COC was exceeded was also calculated using E-
FAST as described in Section 2.3.2. The days of exceedance modeled in E-FAST are not
necessarily consecutive and could occur sporadically throughout the year. For methylene
chloride, continuous aquatic exposures are more likely for the longer exposure scenarios (i.e.,
100-365 days/yr of exceedance of a COC), and more of an interval or pulse exposure for shorter
exposure scenarios (i.e., 1-99 days/yr of exceedances of a COC). Due to the volatile properties of
methylene chloride, it is more likely that a chronic exposure duration will occur when there are
long-term consecutive days of release versus an interval or pulse exposure which would more
likely result in an acute exposure duration.
4.2.2 Risk Estimation for Aquatic Environment
To characterize potential risk from exposures to methylene chloride, EPA calculated RQs based
on modeled data from E-FAST for sites that had surface water discharges of methylene chloride
according to DMR and TRI data (see Table 4-4 and Appendix H.2). EPA modeled surface water
concentrations of methylene chloride for 121 releases from facilities that manufacture, import
and repackage, process, use, and dispose of methylene chloride. Direct releasing facilities
(releases from an active facility directly to surface water) were modeled with two scenarios
based on a high-end and low-end days of release. Indirect facilities (transfer of wastewater from
an active facility to a receiving POTW or non-POTW WWTP facility) were only modeled with a
Page 346 of 753

-------
high-end days of release scenario because it was assumed that the actual release to surface water
would mostly occur at receiving treatment facilities, which were assumed to typically operate greater
than 20 days/yr. As stated in Section 2.3.1.2.2, the maximum release frequency (250 to 365 days) is
based on estimates specific to the facility's condition of use and the low-end release frequency of 20
days of release per year is based on estimated releases that could lead to risk from chronic exposure.
All facilities were modeled in E-FAST and RQs are listed in Appendix H.2. Facilities with RQs
and days of exceedance that indicate risk for aquatic organisms (facilities with an acute RQ > 1,
or a chronic RQ > 1 and 20 days or more of exceedance for the chronic COC) are presented in
Table 4-4. There are four recycling and disposal facilities and one WWTP that indicate risk for
aquatic organisms. Faculties in other conditions of use had acute and chronic RQs < 1, indicating
they do not present acute or risk to aquatic organisms from chronic exposure.
Recycling and Disposal
Of the 16 recycling and disposal facilities, there were 4 sites with releases indicating risk to
aquatic organisms (either the acute RQ > 1, or the chronic RQ > 1 with 20 days or more of
exceedance for the chronic COC). One of these facilities had an acute RQ > 1, indicating risk
from acute exposure. This RQ was associated with indirect releases from a recycling and
disposal facility, Veolia ES Technical Solutions LLC. The facility transferred methylene chloride
for the purpose of wastewater treatment to Clean Harbors POTW. The acute RQ associated with
this release was 6.88, indicating the surface water concentration was almost seven times higher
than the acute COC. Veolia ES Technical Solutions LLC also transferred methylene chloride to
three other facilities; however, those receiving facilities indicated exposures that are less than the
concentration of concern. Middlesex County Utilities Authority had an acute RQ < 1 (indicating
acute exposure is less than the COC), and it was determined after further analysis that Safety-
Kleen Systems Inc and Ross Incineration receiving facilities did not release methylene chloride
to surface water.
Among the recycling and disposal facilities, there were 4 with releases indicating risk from
chronic exposure (where the chronic RQs > 1 and there were 20 days or more of exceedance).
These four facilities had both direct releases to surface water and indirect releases, where waste
was transferred to another facility before it was released. The facility with the highest RQ for this
OES (chronic RQ = 201.11) had an indirect release, the result of a transfer from Veolia ES
Technical Solutions LLC to Clean Harbors POTW for wastewater treatment, as mentioned
above. It is unclear whether Clean Harbors POTW releases methylene chloride to freshwater or
an estuarian environment; however, chronic RQs are greater than or equal to one with 20 days or
more of exceedance for amphibians (RQ = 201.11 with 250 days of exceedance), fish (RQ =
119.87 with 250 days of exceedance), and invertebrates (RQ = 10.06 with 200 days of
exceedance). Two other indirect releases from Johnson Matthey West and Clean Harbors Deer
Park LLC also resulted in chronic RQs > 1 and involved transfers to Clean Harbors Baltimore
(chronic RQ = 1.63 and 1.38, respectively). One direct release from a recycling and disposal
facility resulted in an RQ > 1; Clean Water of New York Inc, had a chronic RQ of 3.92.
As stated previously, the highest modeled release originated from Veolia ES Technical Solutions
LLC. The release was transferred to Clean Harbors of Baltimore (modeled concentration of
18,100 ppb). This concentration is many times higher than the next highest surface water
Page 347 of 753

-------
concentration modeled. To calculate this surface water concentration, EPA used TRI data
indicating that methylene chloride was transferred to Clean Harbors POTW for wastewater
treatment. In the absence of information about how methylene chloride waste was managed or
possibly released at Clean Harbors POTW, EPA used a reasonable default assumption for
assessing releases to surface water. Because the TRI data indicate methylene chloride was
transferred to Clean Harbors Baltimore for wastewater treatment, EPA assumed 54% removal of
methylene chloride before it was released to surface water (the assumption EPA uses for the
POTW industry sector). Site-specific flow data was not available, so instream flow information
representative of industrialized POTWs was used to model subsequent surface water
concentrations. It was not indicated in the TRI data whether the chemical was incinerated on-site
or underwent some other treatment activity.
Wastewater Treatment Plant (WWTP)
For WWTPs, 1 facility, Long Beach (C) WPCP in Long Beach, NY, had an acute RQ > 1 at 2.23
from a direct release of methylene chloride to surface water. This facility releases methylene
chloride into an estuarian environment. Becasue amphibians reside in freshwater environments,
risk for Long Beach (C) WPCP was based on fish. Additionally, a WWTP is likely to be
operating at greater than 20 days of release, therefore the RQ associated with the high-end days
of release scenario (365 days) is likely more representative of actual conditions. The acute RQ
associated with the high-end days of release scenario (365 days) for this site was 0.12, indicating
acute exposure is less than the COC . However, RQs from chronic exposure indicated risk with a
fish RQ of 2.13 and 365 days of exceedance.
Page 348 of 753

-------
Table 4-4. Modeled Facilities Showing Risk from Acute and/or Chronic Exposure from the Release of Methylene Chloride; RQ
Greater Than One are Shown in Bold
Name,
l ocution, iind
II) ol' \cli\e
Releaser
l-acililv'
Release
Media1'
Modeled l-'acilil>
or Indusln Seclor
in li-l-AST'
I.-I- AST
\\ alerhod.t
l\pe'1
Annual
Release
Dajsof
release'
l)ail\
Release
Uvg/dajV
'qui
s\\<
ippbj-
tOt T> pe
tot
IPIIM
l)a\s ol'
r.\ceedance
(da\ s/\ r)h
RQ
OES: Processing: Formulation
EUROFINS
MWG OPERON
LLC
LOUISVILLE,
KYTRI:
4029WRFNSM1
27 IP
POTW
Receiving Facility:
VEOLIA
ENVIRONMENT
AL SERVICES
TECH
SOLUTIONS
LLC; Inorganic
Chemicals Manuf.
Surface
water
5,785
300
19
1659.44
Chronic Amphib.
90
221
18.44
Chronic Fish
151
181
10.99
Chronic Invert.
1,800
21
0.92
Acute Amphib.
2,630
N/A
0.63
SOLVAY-
HOUSTON
PLANT
HOUSTON, TX
NPDES:
TX0007072
Surface
Water
Active Releaser:
NPDES
TX0007072
Surface
water
12
300
0.04
7.15
Chronic Amphib
90
0
0.079
Chronic Fish
151
0
0.047
Chronic Invert.
1,800
0
0.004
Acute Amphib.
2,630
N/A
0.0027
20
0.58
107.41
Chronic Amphib
90
0
1.19
Chronic Fish
151
0
0.71
Chronic Invert.
1,800
0
0.06
Acute Amphib.
2,630
N/A
0.041
OES: Recycling and Disposal
JOHNSON
MATTHEY
WEST
DEPTFORD, NJ
NPDES:
NJ0115843
Non-
POTW
WWT
Receiving Facility:
Clean Harbors of
Baltimore, Inc;
POTW (Ind.)
Surface
water
620
250
2
147.01
Chronic Amphib.
90.0
68
1.63
Chronic Fish
151.0
36
0.97
Chronic Invert.
1800.0
0
0.08
Acute Amphib.
2,630
N/A
0.056
CLEAN
HARBORS
DEER PARK
LLC LA
PORTE, TX
NPDES:
TX0005941
Non-
POTW
WWT
Receiving Facility:
Clean Harbors of
Baltimore, Inc;
POTW (Ind.)
Surface
water
522
250
2
123.89
Chronic Amphib
90.0
56
1.38
Chronic Fish
151.0
28
0.82
Chronic Invert.
1800.0
0
0.07
Acute Amphib.
2,630
N/A
0.047
Page 349 of 753

-------
N;inu'.











Locution. ;iihI











II) ul' Acli\e

Modeled l ;icili(\
l.-IAST
Anniiiil

l):iil\
'qui


l);i\s ol'

Releaser
Release
or 1 ikIiisISector
\\ ;ik'rl)od\
Release
l);i\s ol
Rclcsisc
S\\(

(<><
r.\cccd;incc

l-iicililv1
\ledi;ih
in l.-IAST'
Tj pc'1
(ku>
rclciisc''
(kii/d;i\)'
(|)|)h)-
COC Tjpe
(|)|)b)
(d;i\s/\ n1'
RQ


Receiving Facility:
MIDDLESEX





Chronic Amphib.
90
0
5.60E-
05










3.34E-
05


COUNTY





Chronic Fish
151
0


UTILITIES
AUTHORITY;
Still body
4.40
250
0.018
0.00504





Chronic Invert.
1,800
0
2.80E-
06


NPDES:
NJ0020141















Acute Amphib.
2,630
N/A
1.92E-
06
VEOLIA ES

Receiving Facility:
Clean Harbors;
POTW (Ind.)





Chronic Amphib.
90
250
201.11
TECHNICAL

Surface
76,450.66
250
306
18100
Chronic Fish
151
250
119.87
SOLUTIONS
Non-
water
Chronic Invert.
1,800
200
10.06
LLC
POTW





Acute Amphib.
2,630
N/A
6.88
MIDDLESEX,
NJNPDES:
NJ0127477
WWT
Receiving Facility:
ROSS
INCINERATION
SERVICES INC;





Chronic Amphib.
-
-
-

NA
NA
NA
NA
NA
Chronic Fish
-
-
-


Chronic Invert.
-
-
-


POTW (Ind.)





Acute Amphib.
-
-
-


Receiving Facility:





Chronic Amphib.
-
-
-


SAFETY-KLEEN
NA
NA
NA
NA
NA
Chronic Fish
-
-
-


SYSTEMS INC;
POTW (Ind.)
Chronic Invert.
-
-
-







Acute Amphib
-
-
-
CLEAN
WATER OF
NEW YORK
INC STATEN
ISLAND, NY
NPDES:
NY0200484







Chronic Amphib
90
0
0.31




250
0.01
28.00
Chronic Fish
151
0
0.19

Active Releaser


Chronic Invert.
1,800
0
0.02
Surface
(Surrogate):
Still body
2.38



Acute Amphib
2,630
N/A
0.01
Water
NPDES



Chronic Amphib
90
20
3.92

NJ0000019


20
0.12
352.94
Chronic Fish
151
20
2.34




Chronic Invert.
1800
0
0.20







Acute Amphib
2,630
N/A
0.13
OILTANKING
HOUSTON INC
Surface
Water
Active Releaser
(Surrogate):
Surface
water
1
250
0.003
7.22
Chronic Amphib
90
0
8.02E-
02
Page 350 of 753

-------
N;inu'.
Locution. ;iihI
II) ul' Acli\e
Releaser
l-iicililv1
Release
\ledi;ih
Modeled l ;icili(>
or Indiisin Sector
in l.-IAST'
l.-IAST
\\ ;ilcrhod>
Tj pc'1
Anniiiil
Release
(kii>
Dsijs of
rclc;isc''
l);iil\
Rclcsisc
(kii/d;i\)'
'qui
SWC
(ppl))-
COC Tjpe
COC
(|)|)b)
Dsijs of
r.\cccd;incc
(d;i\s/\ r)1'
RQ
HOUSTON, TX
NPDES:
TX0091855

NPDES
TX0065943





Chronic Fish
151
0
4.78E-
02
Chronic Invert.
1,800
0
4.01E-
03
Acute Amphib
2,630
N/A
2.75E-
03
20
0.041
90.00
Chronic Amphib
90
0
1.00
Chronic Fish
151
0
0.60
Chronic Invert.
1,800
0
0.05
Acute Amphib
2,630
N/A
0.03
OES: WWTP
LONG BEACH
(C) WPCP
LONG BEACH,
NY NPDES:
NY0020567
Surface
Water
Active Releaser:
NPDES
NY0020567
Still water
2,730
365
7
322.14
Chronic Amphib.
90
365
3.58
Chronic Fish
151
365
2.13
Chronic Invert.
1,800
0
0.18
Acute Amphib
2,630
N/A
0.12
20
136.49
5857.02
Chronic Amphib
90
20
65.08
Chronic Fish
151
20
38.79
Chronic Invert.
1,800
20
3.25
Acute Amphib.
2,630
N/A
2.23
i. Facilities actively releasing methylene chloride were identified via DMR and TRI databases for the 2016 reporting year.
j. Release media are either direct (release from active facility directly to surface water) or indirect (transfer of wastewater from active facility to a receiving POTW or non-
POTW WWTP facility). A wastewater treatment removal rate of 57% is applied to all indirect releases, as well as direct releases from WWTPs.
k. If a valid NPDES of the direct or indirect releaser was not available in EFAST, the release was modeled using either a surrogate representative facility in EFAST (based
on location) or a representative generic industry sector. The name of the indirect releaser is provided, as reported in TRI.
1. EFAST uses ether the "surface water" model, for rivers and streams, or the "still water" model, for lakes, bays, and oceans.
m. Modeling was conducted with the maximum days of release per year expected. For direct releasing facilities, a minimum of 20 days was also modeled,
n. The daily release amount was calculated from the reported annual release amount divided by the number of release days per year,
o. For releases discharging to lakes, bays, estuaries, and oceans, the acute scenario mixing zone water concentration was reported in place of the 7Q10 SWC.
p. To determine the PDM days of exceedance for still bodies of water, the estimated number of release days should become the days of exceedance only if the predicted
surface water concentration exceeds the COC. Otherwise, the days of exceedance can be assumed to be zero.
Page 351 of 753

-------
EPA also used surface water monitoring data from the WQP and from the peer reviewed publicly
available literature and grey literature to characterize the risk of methylene chloride to aquatic
organisms in ambient water. From the WPQ, EPA's STORET data and USGS's NWIS data
show an average concentration of methylene chloride of 0.78 1.5 [j,g/L in surface water. These
data reflect 2,286 measurements taken throughout 10 U.S. states between 2013 and 2017. The
highest concentration recorded was 29 |ig/L, measured once in 2016. Very few monitors were
positioned downstream of facilities releasing methylene chloride to surface water, and the
monitors that were downstream were not close. As stated in Section 2.3.2, three of the
monitoring sites were 7.5 to 15.8 miles downstream of two facilities. The remaining monitoring
sites were not collocated with facilities. Therefore, the monitored data from these locations
reflect concentrations of methylene chloride in ambient water, rather than concentrations near
facilities. The monitored data generally show ambient concentrations much lower than the
concentrations modeled close to facilities releasing methylene chloride from the E-FAST results.
This indicates that risk to aquatic organisms from methylene chloride exposure is more likely
proximal to facilities, than in locations farther downstream. Environmental conditions, like wind
speed, water depth, and temperature, will affect how long methylene chloride remains in the
surface water. As stated previously, the estimated volatilization half-life of methylene chloride is
1.1 hours in a modle river and less than 4 days in a model lake.
Table 4-5 shows acute and chronic RQs calculated using the mean surface water concentration
from monitoring data. It also shows an acute RQ of 0.0 (with rounding) and chronic RQs of 0.3,
0.2, and 0.0 calculated using the maximum surface water concentration from the monitored data.
These data indicate that levels less than the COC were identified in ambient water for
amphibians, fish, and aquatic invertebrates exposed to methylene chloride for a chronic duration.
Table 4-5. RQs Calculated using Monitored Environmental Concentrations from WQP
Monitored Surface \Yaler
Concentrations (pph) from
2013-2017
UQ using
Acme cor or
2.630 pph
UQ using
Chronic COC
of 90 pph
UQ using
Chronic COC
of 151 pph
UQ using
Chronic COC or
I.S00 pph
Mean (SD): 0.78 (1.5) ppb
0.0
0.0
0.0
0.0
Maximum: 29 ppb
0.0
0.3
0.2
0.0
To show where facilities releasing methylene chloride to surface water are in relation to
monitored data, EPA used the geospatial analysis outlined in Section 2.3 to conduct a watershed
analysis. This analysis combined predicted concentrations from modeled facility releases with
monitored data from WQP. Overall, there are 28 U.S. states/territories with either a measured
concentration (n=10) or a predicted concentration (n=23). At the watershed level, there are 125
HUC-8 areas and 196 HUC-12 areas with either measured or predicted concentrations
(TableApx E-l and TableApx E-2). The surface water concentrations were compared to the
COCs.
Figure 4-1 through Figure 4-5 show where monitored and modeled surface water concentrations
exceeded the COCs for amphibians, fish, and invertebrates. Figure 4-1 and Figure 4-2 show
exceedances for a maximum days of release scenario, and Figure 4-3 and Figure 4-4 show
Page 352 of 753

-------
exceedances for a 20-days of release scenario. Figure 4-5 shows an area where some monitoring
information was co-located with facilities that release methylene chloride to surface water.
However, the monitoring samples were not down-stream of the facilities and did not detect
methylene chloride in the ambient water.
Page 353 of 753

-------
Concentration Levels	Concentration Type
> 1800(jg/L ~ Modeled - Direct Release (250 - 365 days/yr)
151 - 1799 (jg/L A Modeled - Indirect Release (250 - 365 days/yr)
90  150 |jg/L o Measured - NWIS/STORET Monitoring Sites
< 90 |jg/L (below all COCs) H A Days of exceedance > 20 days
Not detected	States with no modeled or measured concentrations
300
M Miles
Figure 4-1. Surface Water Concentrations of Methylene Chloride from Releasing Facilities
(Maximum Days of Release Scenario) and WQX Monitoring Stations: Year 2016, East U.S.
All indirect releases are mapped at the receiving facility unless the receiving facility is unknown.
Puerto Rico and U.S. Virgin Islands not shown due to no modeled releases or measured monitoring information.
Page 354 of 753

-------
zzzz
300
i Miles
Concentration Type
~ Modeled - Direct Release (250 - 365 days/yr)
A Modeled - Indirect Release (250 - 365 days/yr)
o Measured - NWIS/STORET Monitoring Sites
0 A Days of exceedance > 20 days
States with no modeled or measured concentrations
YZX
Concentration Levels
	> 1800 pg/L
151 - 1799 (jg/L
	90- 150 (jg/L
	<90 |jg/L (below all
Not detected
COCs)
Figure 4-2. Surface Water Concentrations of Methylene Chloride from Releasing Facilities
(Maximum Days of Release Scenario) and WQX Monitoring Stations: Year 2016, West
U.S.
All indirect releases are mapped at the receiving facility unless the receiving facility is unknown.
Alaska, Hawaii, Guam, N. Mariana Islands and American Somoa not shown due to no modeledreleases or measured
monitoring information.
Page 355 of 753

-------
Concentration Levels	Concentration Type
	> 1800 |jg/L	~ Modeled - Direct Release (20 days/yr)
151 - 1799 |jg/L	o Measured - NWIS/STORET Monitoring Sites
	90- 150(jg/L	0 Days of exceedance > 20 days
	< 90 |jg/L (below all COCs) States with no modeled or measured
	Not detected	concentrations
Figure 4-3. Concentrations of Methylene Chloride from Releasing Facilities (20 Days of
Release Scenario) and WQX Monitoring Stations: Year 2016, East U.S.
Puerto Rico and U.S. Virgin Islands not shown due to no modeled releases or measured monitoring information.
Page 356 of 753

-------
MN
CA

AZ
NM
TX
Concentration Levels
in
300
I Miles
Concentration Type
~ Modeled - Direct Release (20 days/yr)
o Measured - NWIS/STORET Monitoring Sites
0 Days of exceedance > 20 days
> 1800 pg/L
151 - 1799 pg/L
90- 150 |jg/L
< 90 |jg/L (below all COCs) w States with no modeled or measured
Not detected

concentrations
Figure 4-4. Concentrations of Methylene Chloride from Methylene Chloride-Releasing
Facilities (20 Days of Release Scenario) and WQX Monitoring Stations: Year 2016, West
U.S.
Alaska, Hawaii, Guam, N. Mariana Islands and American Somoa not shown due to no modeled releases or measured
monitoring information.
Page 357 of 753

-------

IT
CO
NV


ca y
AZ&
NM

_j*


U.S. Locations
Concentrations
Aqua Fria
15070102
\
Pleasant
AZ0020559
AZU0201J01
Theodore
evelt
Apache
Lower Salt
15060106
AZUU235I31
\Z(I020524

I M
50
Miles

Only one HUC-12 contains both
a facility and a monitoring station
J
SGS The National Map: National Hydrography Dataset. Data refreshed October, 2018
Measured - NWIS/STORET Monitoring Sites
 Not detected
Modeled - Direct Release (250 - 365 days/yr)
 Below all COC
H Days of exceedance > 20 days
HUC-8 boundary
I I HUC-12 boundary*
Figure 4-5. Co-location of Methylene Chloride Releasing Facilities and WQX Monitoring
Stations at the HUC 8 and HUC 12 Level
Page 358 of 753

-------
4.2.3	Risk Estimation for Sediment
EPA also quantitatively analyzed exposure to sediment organisms. While no ecotoxicity studies
were available for sediment-dwelling organisms (e.g., Lumbriculus variegatus, Hyalella azteca,
Chironomus riparius), aquatic invertebrates were used as a surrogate species. EPA is uncertain
whether methylene chloride is more or less toxic to daphnia than sediment-dwelling species.
However, because methylene chloride is not expected to sorb to sediment and will instead
remain in pore water, daphnia which feed through the entire water column were deemed to be an
acceptable surrogate species for sediment invertebrates. EPA calculated an acute aquatic
invertebrate COC of 36,000 ppb, and a chronic aquatic invertebrate COC of 1,800 ppb to address
hazards to sediment organisms. Methylene chloride is expected to be in sediment and pore water
with concentrations similar to or less than the overlying water due to its water solubility (13 g/L),
low partitioning to organic matter (log Koc = 1.4), and biodegradability in anaerobic
environments. Thus, methylene chloride concentrations in sediment and pore water are expected
to be similar to or less than the concentrations in the overlying water, and concentrations of
methylene chloride in the deeper part of sediment, where anaerobic conditions prevail, are
expected to be lower.
Therefore, EPA used modeled surface water concentrations to estimate the concentration of
methylene chloride in pore water near facilities. EPA also used monitored data to estimate the
concentration of methylene chloride in pore water in the ambien water. Comparing aquatic
invertebrate data to these exposure numbers, the data showed that there is risk to sediment
dwelling organisms near one facility due to chronic exposure. Table 4-4 shows an RQ from
chronic exposure near Clean Harbors POTW at RQ = 10.1 with 200 days of exceedance for
aquatic invertebrates. In ambient water, for both acute and chronic exposures to methylene
chloride, the RQs are 0.00 and 0.016, based on the highest ambient surface water concentration
of 29 ppb, indicating exposures are less than the COC (RQs < 0) to sediment organisms from
acute or chronic exposures.
4.2.4	Risk Estimation for Terrestrial
During Problem Formulation EPA conducted a screening level analysis to consider whether
pathways of exposure for terrestrial organisms should be further analyzed and determined that
terrestrial organism exposures to methylene chloride was not of concern partially based on
estimates of soil concentrations several orders of magnitude below concentrations observed to
cause effects in terrestrial organisms. EPA did not assess exposure to terrestrial organisms
through soil, land-applied biosolids, or ambient air in this Risk Evaluation. Methylene chloride is
not expected to partition to or accumulate in soil; rather, it is expected to volatilize to air or
migrate through soil into groundwater based on its physical-chemical properties (log Koc = 1.4,
Henry's Law constant = 0.00325 atm-m3/mole, vapor pressure = 435 mmHg at 25C). A
screening of hazard data for terrestrial organisms shows potential hazard; however, physical
chemical properties do not support an exposure pathway through water and soil pathways to
terrestrial organisms. In addition, soil concentrations from the WQP were several orders of
magnitude below concentrations observed to cause effects in terrestrial organisms.
Methylene chloride is not anticipated to be retained in biosolids (processed sludge) obtained
through wastewater treatment. Most methylene chloride present in the water portion of biosolids
following wastewater treatment, processing, and land application would be expected to volatilize
into air. Furthermore, methylene chloride is not anticipated to remain in soil, as it is expected to
Page 359 of 753

-------
either volatilize into air or migrate through soil into groundwater. Therefore, the land application
of biosolids was not analyzed as a pathway for environmental exposure.
Methylene chloride is expected to volatilize to air, based on physical-chemical properties.
However, EPA did not include the emission pathways to ambient air from commercial and
industrial stationary sources or associated inhalation exposure of terrestrial species, because
stationary source releases of methylene chloride to ambient air are covered under the jurisdiction
of the Clean Air Act (CAA). The CAA contains a list of hazardous air pollutants (HAP) and
provides EPA with the authority to add to that list pollutants that present, or may present, a threat
of adverse human health effects or adverse environmental effects. For stationary source
categories emitting HAP, the CAA requires issuance of technology-based standards and, if
necessary, additions or revisions to address developments in practices, processes, and control
technologies, and to ensure the standards adequately protect public health and the environment.
The CAA thereby provides EPA with comprehensive authority to regulate emissions to ambient
air of any hazardous air pollutant.
Methylene chloride is a HAP. EPA has issued a number of technology-based standards for
source categories that emit methylene chloride to ambient air and, as appropriate, has reviewed,
or is in the process of reviewing remaining risks. Because stationary source releases of
methylene chloride to ambient air are addressed under the CAA, EPA is not evaluating emissions
to ambient air from commercial and industrial stationary sources or associated inhalation
exposure of the general population or terrestrial species in this TSCA risk evaluation.
Additionally, based on the Guidance for Ecological Soil Screening Levels (	33a. b)
document, for wildlife, relative exposures associated with inhalation and dermal exposure
pathways are insignificant compared to direct ingestion of food or water contaminated with
methylene chloride (by approximately 1,000-fold). Therefore, volitalization from surface water
and biosolids to air of methylene chloride is not a concern for wildlife.
4.3 Human Health Risk
Methylene chloride exposure is associated with a variety of cancer and non-cancer adverse
effects deemed relevant to humans for risk estimations for the scenarios and populations
addressed in this risk evaluation. Based on a weight-of-evidence analysis of the available toxicity
studies from animals and humans, the non-cancer effects selected for risk estimation because of
their robustness and sensitivity were neurotoxicity (i.e., CNS depression) from acute exposure
and liver toxicity from chronic exposures. The evaluation of cancer includes estimates of risk of
lung and liver tumors. Although irritation and burns may result from exposure to methylene
chloride, air concentrations leading to eye and respiratory tract irritation are not well established,
nor are concentrations resulting in direct contact burns to skin or eyes.
4.3.1 Risk Estimation Approach
Table 4-6, Table 4-7, and Table 4-8 show the use scenarios, populations of interest and
toxicological endpoints used for acute exposures for workers, acute exposure for consumers
and chronic exposure for workers, respectively.
Page 360 of 753

-------
Table 4-6. Use Scenarios, Populations of Interest and Toxicological Endpoints for Assessing
Occupational Risks Following Acute Exposures to Methylene Chloride	
Populalions iiiid Toxicologic;!!
Approach
Occupational I se Scenarios of \lclh\lcne Chloride
Population of Interest and
Exposure Scenario:
Users:
Adults and youth of both sexes (>16 years old) exposed to methylene chloride during an 8-
hr workday 1,2
Occupational Non-user:
Adults and youth of both sexes (>16 years old) indirectly exposed to methylene chloride
while being in the same building during product use and further information when
available is included in section 2.4.1.2 listed by OES. Workers include 16-year olds
because of OSHA work permits.
Health Effects of Concern,
Concentration and Time
Duration
Non-Cancer Health Effects: Acute toxicity CNS degression.
Hazard Values (PODs) for Occupational Scenarios:3-4
	15-min: 478 ppm (1706 mg/m3)
	1-hr: 240 ppm (840 mg/m3)
	8-hrs: 80 ppm (290 mg/m3)
Cancer Health Effects: Cancer risks following acute exposures were not estimated.
Relationship is not known between a single short-term exposure to methylene chloride
and the induction of cancer in humans.
Uncertainty Factors (UF)
used in Non-Cancer
Margin of Exposure (MOE)
calculations
Total UF = 30 (10X UFH * 3X UHL)5
Notes:
1	It is assumed no substantial buildup of methylene chloride in the body between exposure events due to methylene
chloride's short biological half-life (~40 min).
2	EPA believes that the users of these products are generally adults.
3	Exposure estimates were made for 8 hr TWAs for all the conditions of use and when exposure estimates for times shorter
than 8 hrs were made the additional PODs (identified above) were used.
4
In addition to the PODs identified, EPA also compared higher exposure values ( > 4000 mg/m3) with the NIOSHIDLH
value of 7981 mg/m3. which is the value identified as immediatelv dangerous to life or health (NIOSH. 1994); individuals
should not be exposed to this level for any length of time.
5	UFH=intraspecies UF; UFL=LOAEL to NOAEL UF
Page 361 of 753

-------
Table 4-7. Use Scenarios, Populations of Interest and Toxicological Endpoints for Assessing
Consumer Risks Following Acute Exposures to Methylene Chloride
1 so
Scenarios

Populations
and Toxicological^^
Approach
CONSl MIR I SI S
I'opulalion of Inleresl
and r.xposure Scenario:
I MTS
Adults of both sexes (>16 years old) typically exposed to methylene chloride.
I'opulalion ol Inleresl
and llxposmv Scenario:
Hyshmdcr
Individuals of any age indirectly exposed to methylene chloride while being in the rest
of the house during product use see Section 2.4.2 for more information.

Non-Cancer Health Effects: CNS effects
Health I'.ITeclsof
( oncern. ( onccnl ralion
and Time l)uration
Hazard Values (PODsj for Consumer Scenarios3:
	15-min: 478 ppm (1706 mg/m3)
	1-hr: 240 ppm (840 mg/m3)
	8-hrs: 80 ppm (290 mg/m3)
Cancer Health Effects: Cancer risks following acute exposures were not estimated.
I ncorla in l> l-'aclors (I I )
used in \on-( ancer
Margin ol l-lxposure
(MOT.) calculalions
Total UF = 30 (10X UFH * 3X UHL)4
Notes:
1	It is assumed no substantial buildup of methylene chloride in the body between exposure events due to methylene
chloride's short biological half-life (~40 min).
2	EPA believes that the users of these products are generally adults, but younger individuals may be users of
methylene chloride products
3In addition to the PODs identified, EPA also compared higher exposure values ( > 4000 mg/m3) with the NIOSH
IDLH value of 7981 mg/m3. which is the value identified as immediately danserous to life or health (NIOSH.
1994); individuals should not be exposed to this level for anv leneth of time.
4 UFH= intraspecies UF; UFL=LOAEL to NOAEL UF
Page 362 of 753

-------
Table 4-8. Use Scenarios, Populations of Interest and Toxicological Endpoints for Assessing
Occupational Risks Following Chronic Exposures to Methylene Chloride	
1 so
Scenarios
Populations^^
And Toxicologicitk
Approach
()( ( I I'ATIOWI. 1 Si-
I'opulalion ol Inlcresl
and llxposiiiv
Scenario:
I MT.S
Adults of both sexes (>16 years old) exposed to methylene chloride during
an 8-hr workday for up to 250 days/yr for as many as 40 working years depending on
the occupational scenario 1 -23
I'opulalion ol Inlcresl
and llxposiiiv
Scenario:
.\oii-nscr
Adults of both sexes (>16 years old) indirectly exposed to methylene chloride while
being in the same building during product use.3
Health HITccls of
Concern.
( oncenIralion and
l ime Duralion
Hazard Value (PODs) Hazard Value (PODs)
for Non-Cancer Effects for Cancer Effects
(liver effects): (liver and lung tumors):
1st percentile HEC i.e., the HEC99: IUR:
HEC i.e., the HEC99: 1.38 x 10~6 per mg/m3
17.2 mg/m3 for 40 hr work week
(4.8 ppm)
for 24 hr/day exposure
I nccrlainl> l-'aclors
(I I") used in Non-
Cancer
Margin of llxposiiiv
(MOT.) ca leu la I ions
UF for the HEC99 = 10 (3X UFA * 3X UHh)
UF is not applied for the cancer risk calculations.
Notes:
1	It is assumed no substantial buildup of methylene chloride in the body between exposure events due to
methylene chloride's short biological half-life (~40 min).
2	EPA believes that the users of these products are generally adults.
3	A range of working years were evaluated from 31 - 40 years, see Section 2.4.1.1.
4	Data sources did not often indicate whether exposure concentrations were for occupational users or non-users.
Therefore, EPA assumed that exposures were for a combination of users and non-users. Some non-users may
have lower exposures than users, especially when they are further away from the source of exposure.
Page 363 of 753

-------
Acute or chronic MOEs (MOEaCute or MOEchronic) were used in this assessment to estimate non-
cancer risks using Eq. 4-1
(Eq. 4-1)
Equation to Calculate Non-Cancer Risks Following Acute or Chronic Exposures Using
MOEs
Non  cancer Hazard value (POD)
MOEacuteorchronlc =	Human Exposure
Where:
MOE = Margin of exposure (unitless)
Hazard value (POD) = POD or HEC (mg/m3 or mg/kg/day)
Human Exposure = Exposure estimate (mg/m3 or mg/kg/day) from occupational or consumer
exposure assessment (see Section 2.4).
EPA used MOEs22 to estimate risks from acute and chronic exposure for non-cancer effects based
on the following:
1.	the endpoint/study-specific UFs applied to the HECs per EPA Guidance (EPA. 2002): and
2.	the exposure estimates calculated for methylene chloride uses examined in this risk
evaluation (see Section 2.4).
MOEs allow for the presentation of a range of risk estimates. The OES considered both acute and
chronic exposures. All consumer uses considered only acute exposure scenarios. Different adverse
endpoints were determined to be appropriate based on the expected exposure durations. For non-
cancer effects, risks for acute effects (neurotoxicity) were evaluated for acute (short-term)
exposures, whereas risks for liver toxicity were evaluated for repeated (chronic) exposures to
methylene chloride. For cancer, risks for chronic effects are based on lung and liver tumors. EPA
discusses other effects in Sections 3.2.3 and 3.2.4.
For occupational exposure calculations, the 8 hr TWA was used to calculate MOEs for risk
estimates for acute and chronic exposures. When shorter duration exposure estimates were
available (e.g., 15 minutes or 1 hr), these were used to calculate MOEs for risk estimates for
acute exposures. EPA selected exposure durations of 15 mins and 1 hr, in addition to the 8-hr
duration to represent a reasonable range of acute exposure durations. Also, in one fatality case
report, the exposed individual was found dead 20-30 mins after the individual had been observed
alive (Nac/Aegl. 2008b). Even though the individual may have been exposed for some time prior
to being still observed alive, additional information was not available and thus, the total exposure
time could have been limited. Finally, 15 mins matches the duration of the OSHA STEL. For
these reasons, EPA is presenting this range of acute durations when exposure data are available
to calculate such risks.
22 Margin of Exposure (MOE) = (Non-cancer hazard value, POD) (Human Exposure). Equation 4-1. The
benchmark MOE is used to interpret the MOEs and consists of the total UF shown in Table 4-3, Table 4-4 and Table
4-5.
Page 364 of 753

-------
The total UF for each non-cancer POD was developed as the benchmark MOE used to interpret
the MOE risk estimates for each use scenario. The MOE estimate was interpreted as a human
health risk if the MOE estimate was less than the benchmark MOE (i.e., the total UF). On the
other hand, the MOE estimate indicated negligible concerns for adverse human health effects if
the MOE estimate was equal to or exceeded the benchmark MOE. Typically, the larger the MOE,
the more unlikely it is that a non-cancer adverse effect would occur.
Extra cancer risks for chronic exposures to methylene chloride were estimated using Eq 4-2.
Estimates of extra cancer risks should be interpreted as the incremental probability of an
individual developing cancer over a lifetime as a result of exposure to the potential carcinogen
(i.e., incremental or extra individual lifetime cancer risk).
(Eq. 4-2)
Equation to Calculate Extra Cancer Risks
Risk = Human Exposure x Slope Factor
Where:
Risk = Extra cancer risk (unitless)
Human exposure = Exposure estimate (mg/m3 ormg/kg/day) from occupational exposure
assessment
Slope Factor = Inhalation unit risk (1.38E-06 per mg/m3) or
Dermal slope factor (1.1 x 10"5 per mg/kg/day)
Exposures to methylene chloride were evaluated by inhalation and dermal routes separately.
Inhalation and dermal exposures are assumed to occur simultaneously for workers and
consumers.
4.3.2 Risk Estimation for Inhalation and Dermal Exposures
The acute inhalation and dermal risk assessment used CNS effects to evaluate the risks from
acute exposure for consumer and occupational use of methylene chloride. Both non-cancer liver
effects and cancer liver and lung tumors were used to evaluate risk from chronic exposure. Non-
cancer risk estimates were calculated with equation 4-1 and cancer risks were calculated with
equation 4-2.
4.3.2,1 Risk Estimation for Inhalation Exposures to Workers
4.3.2.1.1 Occupational Inhalation Exposure Summary and PPE Use
Determination by OES
EPA considered all reasonably available data for estimating exposures for each OES. EPA also
determined whether air-supplied respirator use up to APF = 50 was plausible for those OES
based on expert judgement and reasonably available information. Table 4-9 presents this
information below, which is considered in the risk characterization for each OES in the
following sections.
Page 365 of 753

-------
Table 4-9. Inhalation Exposure Data Summary and Respirator Use Determination
Occupiilioiiiil
Kxposmv
Scenario
Inhiiliilion
Kxposuiv
Approach
Number of
l)iil;i
Points
Model I sod
Approach lor
OM s
Kcspii'iilor
Usc
Indiislriid or
( OIllllHMViid
OI.S
Manufacturing
Monitoring
data
438 (15
min, 30
min, 1-hr,
8-hr and
12-hr
TWA)
N/A-
monitoring
data only
Equal to
workers
(assumes
employees may
be workers or
ONUs
throughout their
shift)
May use
respirators
Industrial
Processing as a
Reactant
Monitoring
data
30 (15 min,
8-hr TWA)
N/A-
monitoring
data only
Equal to
workers
(assumes
employees may
be workers or
ONUs
throughout their
shift)
May use
respirators
Industrial
Processing -
Incorporation
into
Formulation,
Mixture, or
Reaction
Product
Monitoring
data
55 (8-hr
TWA)
N/A-
monitoring
data only
Equal to
workers
(assumes
employees may
be workers or
ONUs
throughout their
shift)
May use
respirators
Industrial
Repackaging
Monitoring
data
9 (30 min,
1-hr, 8-hr
TWA)
N/A-
monitoring
data only
Equal to
workers
(assumes
employees may
be workers or
ONUs
throughout their
shift)
May use
respirators
Industrial
Waste
Handling,
Disposal,
treatment, and
Recycling
Monitoring
data
30 (30 min,
2-hr, 3-hr,
8-hr TWA)
N/A-
monitoring
data only
Equal to
workers
(assumes
employees may
be workers or
ONUs
throughout their
shift)
May use
respirators
Industrial
Page 366 of 753

-------
()eeup;ilioiiid
KxpoSIIIV
Seen;irio
Inhiiliilion
l'.\|)()SIIIV
Approiieh
Number of
l)iil;i
Points
Model I sod
Appi'Oiich I'or
OM s
Kcspii'iilor
Use
Indusli'iid oi*
Com inereiid
OI.S
Batch Open-
Top Vapor
Degreasing
Model
N/A-
model only
Batch Open-
Top Vapor
Degreasing
Near-
Field/Far-
Field
Inhalation
Exposure
Model
Far-field model
results
May use
respirators
Industrial
Conveyorized
Vapor
Degreasing
Model
N/A-
model only
Conveyorized
Degreasing
Near-
Field/Far-
Field
Inhalation
Exposure
Model
Far-field model
results
May use
respirators
Industrial
Cold Cleaning
Monitoring
data
supplemented
by model
>3 (8-hr
TWA)
Cold
Cleaning
Near-
Field/Far-
Field
Inhalation
Exposure
Model
Equal to
workers
(assumes
employees may
be workers or
ONUs
throughout their
shift)
May use
respirators
Industrial
Commercial
Aerosol
Products
(Aerosol
Degreasing,
Aerosol
Lubricants,
Automotive
Care Products)
Monitoring
data
supplemented
by model
21 (8-hr
TWA)
Aerosol
Degreasing
Near-
Field/Far-
Field
Inhalation
Exposure
Model
Far-field model
results
May use
respirators
Commercial
Adhesives and
Sealants
Monitoring
data
103 for
non-spray
(15 min, 8-
hr), 25 for
spray (15
min, 1-hr,
8-hr
TWA), and
468 for
unknown
application
(8-hr
TWA)
N/A-
monitoring
data only
Equal to
workers
(assumes
employees may
be workers or
ONUs
throughout their
shift)
May use
respirators
Industrial
Page 367 of 753

-------
()eeup;ilioiiid
KxpoSIIIV
Seen;irio
Inhiiliilion
l'.\|)()SIIIV
Approiieh
Number of
l)iil;i
Points
Model I sod
Approiieh I'or
OM s
Kcspii'iilor
Use
Indusli'iid oi*
Com inereiid
OI.S
Paint and
Coatings
Monitoring
data
36 for
spray (15
min, 30
min,8-hr
TWA) and
271 for
unknown
application
(15 min, 30
min, 1-hr,
8-hr TWA)
N/A-
monitoring
data only
Equal to
workers
(assumes
employees may
be workers or
ONUs
throughout their
shift)
May use
respirators
Industrial/
Commercial
Paint and
Coating
Removers
Monitoring
data
>1,342(15
min, 30
min, 1-hr,
8-hr TWA)
N/A-
monitoring
data only
Equal to
workers
(assumes
employees may
be workers or
ONUs
throughout their
shift)
May use
respirators
Industrial/
Commercial
Adhesives and
Caulk
Removers
Surrogate
Monitoring
data for Paint
Stripping by
Professional
Contractors
>42 (< 1-
hr, 2-hr, 8-
hr TWA)
N/A-
monitoring
data only
Equal to
workers
(assumes
employees may
be workers or
ONUs
throughout their
shift)
May use
respirators
Commercial
Miscellaneous
Non-Aerosol
Commercial
and Industrial
Uses
Monitoring
data
108 (8-hr
TWA)
N/A-
monitoring
data only
Equal to
workers
(assumes
employees may
be workers or
ONUs
throughout their
shift)
May use
respirators
Industrial/
Commercial
Fabric
Finishing
Monitoring
data
41 (3-hr, 8-
hr TWA)
N/A-
monitoring
data only
Equal to
workers
(assumes
employees may
be workers or
ONUs
May use
respirators
Industrial/
Commercial



throughout their
shift); 1 ONU
data point


Page 368 of 753

-------
Occupiilioiiiil
K\p0SIIIV
Scenario
Inhiiliilion
l'.\|)()SIIIV
Approiich
Number of
l)iil;i
Points
Model I sod
Approach lor
OM s
Kcspii'iiloi'
Use
Induslriiil or
CoiniiH'iviid
OI.S
Spot Cleaning
Monitoring
data
18 (8-hr
TWA)
N/A-
monitoring
data only
Equal to
workers
(assumes
employees may
be workers or
ONUs
throughout their
shift)
May use
respirators
Commercial
Cellulose
Triacetate Film
Production
Monitoring
data
>166 (8-hr
TWA)
N/A-
monitoring
data only
Equal to
workers
(assumes
employees may
be workers or
ONUs
throughout their
shift)
May use
respirators
Industrial
Plastic Product
Manufacturing
Monitoring
data
85 (83
workers
and 2
ONUs, 15
min, 30
min, 8-hr
TWA)
N/A-
monitoring
data only
ONU
monitoring data
available
May use
respirators
Industrial
Flexible
Polyurethane
Foam
Manufacturing
Monitoring
data
92 (30 min,
6-hr, 8-hr
TWA)
N/A-
monitoring
data only
Equal to
workers
(assumes
employees may
be workers or
ONUs
throughout their
shift)
May use
respirators
Industrial
Laboratory
Use
Monitoring
data
103 (15
min, 30
min, 1-hr,
2-hr, 3-hr,
4-hr, 8-hr)
N/A-
monitoring
data only
Equal to
workers
(assumes
employees may
be workers or
ONUs
throughout their
shift)
May use
respirators
Industrial
Lithograph
Printing Plate
Cleaning
Monitoring
data
>130 (4-hr,
8-hr TWA)
N/A-
monitoring
data only
Equal to
workers
(assumes
employees may
be workers or
ONUs
throughout their
shift)
May use
respirators
Commercial
Page 369 of 753

-------
4.3.2.1.2 Manufacturing
Estimates of MOEs for acute and chronic exposures and cancer risks from inhalation for
manufacturing are presented in Table 4-10, Table 4-11, and Table 4-12, respectively. For
manufacturing exposure estimates for TWAs of 15 mins, 1 hr, and 8 hrs, are available based on
personal monitoring data samples, including 136 data points from 2 sources (Halogenated
Solvents Industry Alliance. 2018). The 15 mins and 1 hr TWAs are useful for characterizing
exposures shorter than 8 hrs that could lead to adverse CNS effects. PODs specific to 15 mins
and 1 hr TWA exposures were used for characterization of the risk. EPA calculated 50th and 95th
percentiles to characterize the central tendency and high-end exposure estimates, respectively.
EPA has not identified data on potential ONU inhalation exposures from methylene chloride
manufacturing. ONU inhalation exposures are expected to be lower than worker inhalation
exposures however the relative exposure of ONUs to workers cannot be quantified as described
in more detail above in Section 2.4.1.2.1. EPA calculated risk estimates assuming ONU
exposures could be as high as worker exposures as a high-end estimate and there is large
uncertainty in this assumption. Considering the overall strengths and limitations of the data,
EPA's overall confidence in the occupational inhalation estimates in this scenario is medium to
high. Section 2.4.1.2.1 describes the justification for this occupational scenario confidence
rating. The studies that support the health concerns of acute CNS effects, liver toxicity and
cancer and the hazard value and benchmark MOEs are described above in Section 4.3.1 Risk
Estimation Approach and overall EPA has medium confidence in the acute, chronic and cancer
endpoints. Section 3.2.5.3 describes the justification for these confidence levels.
Table 4-10. Risk Estimation for Acute, Non-Cancer Inhalation Exposures for
Manufacturing
III.( l ime Period
l.nripoini = ( NS I-'. Heels'
Acme MIX
(ing/iir')
l'l\|)
-------
Table 4-11. Risk Estimation for Chronic, Non-Cancer Inhalation Exposures for
Manufacturing			
r.nripoinl
Chronic
lll(
Img/iiv')
l''.\])
-------
4.3.2.1.3 Processing as a Reactant
Estimates of MOEs for acute and chronic exposures and cancer risks from inhalation for
processing as a reactant are presented in Table 4-13, Table 4-14, and Table 4-15, respectively.
For processing as a reactant exposure estimates for TWAs of 15 min and 8 hrs are available
based on personal monitoring data samples, including 29 data points from two sources
(Halogenated Solvents Industry Alliance. 2018); (Finkel. 2017). The 15 mins TWAs are useful
for characterizing exposures shorter than 8 hrs that could lead to adverse CNS effects. PODs
specific to 15 mins TWA exposures were used for characterization of the risk. EPA calculated
50th and 95th percentiles to characterize the central tendency and high-end exposure estimates,
respectively. EPA has not identified data on potential ONU inhalation exposures from methylene
chloride processing as a reactant. ONU inhalation exposures are expected to be lower than
worker inhalation exposures however the relative exposure of ONUs to workers cannot be
quantified as described in more detail above in Section 2.4.1.2.2. EPA calculated risk estimates
assuming ONU exposures could be as high as worker exposures as a high-end estimate and there
is large uncertainty in this assumption. Considering the overall strengths and limitations of the
data, EPA's overall confidence in the occupational inhalation estimates in this scenario is
medium to high. Section 2.4.1.2.2 describes the justification for this occupational scenario
confidence rating. The studies that support the health concerns of acute CNS effects, liver
toxicity and cancer and the hazard value and benchmark MOEs are described above in Section
4.3.1 Risk Estimation Approach and overall EPA has medium confidence in the acute, chronic
and cancer endpoints. Section 3.2.5.3 describes the justification for these confidence levels.
Table 4-13. Risk Estimation for Acute, Non-Cancer Inhalation Exposures for Processing as
a Reactant
MIX lime Period
l.mlpoint = ( NS HITeels1
Anile MIX
(niii/mM
l'l\|)OMIIV l.l'M'l
MOI-'.s lor Aeu
Worker* OM :
No respii'iilor
(e i:\posui-es
Worker
API- 254
lienchniiirk
MOI.
(= loliil
I I)
8-hr
290
High End
2.7
67
30
Central Tendency
178
4441
15-min
1706
Point Estimate3
4.9
122
30
1	Data from Putz et al. (1979)
2	Exposures to ONUs were not able to be estimated separately from workers.
3	Exposure data were not available to characterize the central tendency and high-end exposures.
4	APF 25 and APF 50 are the two lowest APF allowable under OSHA standards for methylene chloride and are
considered plausible for respirator use. APF 50 not shown based on MOEs at APF 25 are all greater than the
benchmark MOE.
Page 372 of 753

-------
Table 4-14. Risk Estimation for Chronic, Non-Cancer Inhalation Exposures for Processing
as a Reactant
l-'udpt tinl1
('limine
MIX
(iiili/nr1)
l''.\poslll'C I.C\cl
MOI'.s I'm-( limn
Worker* OM :
No respirator
ie r.\|)osure
Worker
API- 25'
lieiichmark
MOI.
(= loliil
I I)
Liver Effects
17.2
High End
0.70
17
10
Central Tendency
46
1154
1	Data from Nitschke et al. (198831
2	Exposures to ONUs were not able to be estimated separately from workers.
3	APF 25 and APF 50 are the two lowest APF allowable under OSHA standards for methylene chloride and are
considered plausible for respirator use. APF 50 not shown based on MOEs at APF 25 are all greater than the
benchmark MOE.
Table 4-15. Risk Estimation for Chronic, Cancer Inhalation Exposures for Processing as a
Reactant
I'lndpoini. Tumor
lApes1
11 K
(risk per iiiii/m-4
l-lxposure l.c\cl
(ancer Risk I'.sliniiiles
Worker* OM :
No respirator*
liciichmark
Cancer Risk
Liver and lung tumors
1.38E-06
High End
7.63E-05
104
Central Tendency
8.95E-07
1 Data from N IP (.1.986)
9
Exposures to ONUs were not able to be estimated separately from workers.
3 Cancer risks with respirators not shown based on cancer risks without respirators are less than the benchmark
cancer risk of 10~4.
4.3.2.1.4 Processing - Incorporation into Formulation, Mixture, or Reaction
Product
Estimates of MOEs for acute and chronic exposures and cancer risks from inhalation for
processing - incorporation into formulation, mixture, or reaction product are presented in Table
4-16, Table 4-17, and Table 4-18, respectively. For processing - incorporation into formulation,
mixture, or reaction product exposure estimates for TWAs of 15 mins and 8 hrs are available
based on personal monitoring data samples, including a range of values for more than 55 samples
from four sources (EPA. 1985); (Finkel. i _ ). The 15 mins TWAs are useful for characterizing
exposures shorter than 8 hrs that could lead to adverse CNS effects. PODs specific to 15 mins
TWA exposures were used for characterization of the risk. EPA calculated 50th and 95th
percentiles to characterize the central tendency and high-end exposure estimates, respectively.
EPA has not identified data on potential ONU inhalation exposures from methylene chloride
processing - incorporation into formulation, mixture, or reaction product. ONU inhalation
exposures are expected to be lower than worker inhalation exposures however the relative
exposure of ONUs to workers cannot be quantified as described in more detail above in Section
2.4.1.2.3. EPA calculated risk estimates assuming ONU exposures could be as high as worker
exposures as a high-end estimate and there is large uncertainty in this assumption. Considering
the overall strengths and limitations of the data, EPA's overall confidence in the occupational
Page 373 of 753

-------
inhalation estimates in this scenario is medium. Section 2.4.1.2.3 describes the justification for
this occupational scenario confidence rating. The studies that support the health concerns of
acute CNS effects, liver toxicity and cancer and the hazard value and benchmark MOEs are
described above in Section 4.3.1 Risk Estimation Approach and overall EPA has medium
confidence in the acute, chronic and cancer endpoints. Section 3.2.5.3 describes the justification
for these confidence levels.
Table 4-16. Risk Estimation for Acute, Non-Cancer Inhalation Exposures for Processing -
Incorporation into Formulation, Mixture, or Reaction Product	i	
lir.C Time Period
l.nripoim = ( NS
i:nwis'
Acme
MIX
img/nr')
l-'.\posurc l.c\cl
MOI-'.s lor
Worker & OM :
No rcspimlor
Acule llxposm
Worker
API- 254
e
W orkcr
API- 504
licnchniiirk
MOI.
(= loliil
I 1)
8-hr
290
High End
0.54
13.5
27
30
Central
Tendency
2.9
71.3
143
15-min
1706
Point Estimate3
9.5
237
474
30
1	Data from Putz et al. (1979)
2	Exposures to ONUs were not able to be estimated separately from workers; also, this scenario covers a broad range
of industries and processes, which may result in significant differences between central and high-end exposures.
3	Exposure data were not available to characterize the central tendency and high-end exposures.
4	APF 25 and APF 50 are the two lowest APF allowable under OSHA standards for methylene chloride and are
considered plausible for respirator use.
The MOEs are less than the benchmark MOE for high end exposures and the estimated 15-
minute exposure when respirators are not worn. The MOEs are greater than benchmark MOEs
when respirators APF 25 are worn except for high end exposure estimates, which are less than
the benchmark at both APF 25 and 50.
Table 4-17. Risk Estimation for Chronic, Non-Cancer Inhalation Exposures for Processing
- Incorporation inl
o Formulation, Mixture, or B
Reaction Product
l.nripoim1
Chronic NIK
(inii/iii'4)
l-'.\posurc
1 .c\ el
MOI-'.s lor
Worker & OM :
No rcspiriilor
C hronic l'.\
Worker
API- 25s
)osurc
W orkcr
API- 50*
licnchniiirk
MOI.
(= loliil
I 1)
Liver Effects
17.2
High End
0.14
3.5
7.0
10
Central
Tendency
0.74
18.5
37.0
1	Data from Nitschke et al. (1988a)
2	Exposures to ONUs were not able to be estimated separately from workers; also, this scenario covers a broad range
of industries and processes, which may result in significant differences between central and high-end exposures.
3	APF 25 and APF 50 are the two lowest APF allowable under OSHA standards for methylene chloride and are
considered plausible for respirator use.
Page 374 of 753

-------
Table 4-18. Risk Estimation for Chronic, Cancer Inhalation Exposures for Processing -
Incorporation into Formulation, Mixture, or Reaction Product	
I'lmlpoini. Tumor
Tjpes1
11 K
(risk per
nig/nr')
Exposure l.c\cl
Cancer Risk I-
Worker* OM :
No respirator
slimalcs
Worker
API- 25'
benchmark
Cancer Risk
Liver and lung tumors
1.38E-06
High End
3.81E-04
1.52E-05
104
Central Tendency
5.58E-05
2.23E-06
1 Data from NTP (1986)
9
Exposures to ONUs were not able to be estimated separately from workers; also, this scenario covers a broad range
of industries and processes, which may result in significant differences between central and high-end exposures.
3 APF 25 and APF 50 are the two lowest APF allowable under OSHA standards for methylene chloride and are
considered plausible for respirator use. APF 50 not shown based on cancer risks at APF 25 are all less than the
cancer risk benchmark of 10~4
4.3.2.1.5 Repackaging
Estimates of MOEs for acute and chronic exposures and cancer risks from inhalation for
repackaging are presented in Table 4-19, Table 4-20, and Table 4-21, respectively. For
repackaging exposure estimates for TWAs of 1 hr and 8 hrs are available based on personal
monitoring data samples, including 5 data points from 1 source (Unocal Corporation. 1986). The
1 hr TWAs are useful for characterizing exposures shorter than 8 hrs that could lead to adverse
CNS effects. PODs specific to 1 hr TWA exposures were used for characterization of the risk.
EPA assessed the median value as the central tendency and the maximum reported value as the
high-end exposure estimate. EPA has not identified data on potential ONU inhalation exposures
from methylene chloride repackaging. ONU inhalation exposures are expected to be lower than
worker inhalation exposures however the relative exposure of ONUs to workers cannot be
quantified as described in more detail above in Section 2.4.1.2.4. EPA calculated risk estimates
assuming ONU exposures could be as high as worker exposures as a high-end estimate and there
is large uncertainty in this assumption. Considering the overall strengths and limitations of the
data, EPA's overall confidence in the occupational inhalation estimates in this scenario is
medium to low. Section 2.4.1.2.1 describes the justification for this occupational scenario
confidence rating. The studies that support the health concerns of acute CNS effects, liver
toxicity and cancer and the hazard value and benchmark MOEs are described above in Section
4.3.1 Risk Estimation Approach and overall EPA has medium confidence in the acute, chronic
and cancer endpoints. Section 3.2.5.3 describes the justification for these confidence levels.
Table 4-19. Risk Estimation for Acute. Non-Cancer Inhalation Exposures for Repackaging
MIX l ime Period
l.nripoinl = CNS
KITccls1
Acule
MIX
(111 Si/lll')
l-lxposurc
l.c\cl
Mor.s r<
Worker* ONI :
No respirator
ii' Acule l-'.\pos
Worker
API- 25'
ii res
W orkcr
API- 50'
licnchmark
MOI.
(= loial I 1)
8-hr
290
High End
2.1
53
105
30
Central
Tendency
33
822
1643
1-hr
840
High End
2.6
64
129
30
Central
Tendency
4.7
118
236
Page 375 of 753

-------
1 Data from Putz et al. (1979)
2Exposures to ONUs were not able to be estimated separately from workers; also, this scenario covers a broad range
of industries and processes, which may result in significant differences between central and high-end exposures.
3 APF 25 and APF 50 are the two lowest APF allowable under OSHA standards for methylene chloride and are
considered plausible for respirator use.
Table 4-20. Risk Estimation for Chronic, Non-Cancer Inhalation Exposures for
Repackaging				
r.nripoinl1
Chronic
NIC
(inii/in1)
l-lxpoMirc
l.c\cl
MOI-'.s In
Worker* OM :
No rcs|>ir;ilor
r Chronic l.xj
W orkcr
API- 25'
tosiircs
W orkcr
API- 50'
licnchmark
MOI.
(= loliil
I 1)
Liver Effects
17.2
High End
0.55
14
27
10
Central
Tendency
8.54
213
427
1	Data from Nitschke et al. (.1.98831
2	Exposures to ONUs were not able to be estimated separately from workers; also, this scenario covers a broad range
of industries and processes, which may result in significant differences between central and high-end exposures.
3	APF 25 and APF 50 are the two lowest APF allowable under OSHA standards for methylene chloride and are
considered plausible for respirator use.
Table 4-21. Risk Estimation for Chronic, Cancer Inhalation Exposures for Repackaging
l-lnripoinl. Tumor
Tjpes"
11 K
(risk per ing/nr')
i:\posiii-e l.e\cl
Cancer Risk llsliniales
Worker* OM :
No respirator*
benchmark
Cancer Risk
Liver and lung tumors
1.38E-06
High End
9.74E-05
104
Central Tendency
4.84E-06
1 Data from NTP (1986)
9
Exposures to ONUs were not able to be estimated separately from workers.
3 APF 25 and APF 50 are the two lowest APF allowable under OSHA standards for methylene chloride and are
considered plausible for respirator use. Cancer risks with respirators not shown based on cancer risks without
respirators are less than the cancer risk benchmark of 10~4.
4.3.2.1.6 Waste Handling, Disposal, Treatment, and Recycling
Estimates of MOEs for acute and chronic exposures and cancer risks from inhalation for waste
handling, disposal, treatment and recycling are presented in Table 4-22, Table 4-23, and Table
4-24, respectively. For waste handling, disposal, treatment and recycling exposure estimates for
TWAs of 8 hrs are available based on personal monitoring data samples, including 22 data points
from four sources (Defense Occupational and Environmental Health Readiness System -
Industrial Hygiene tliOEHRS-IBi 2018; Finkel :0l	EPA calculated 50th and
95th percentiles to characterize the central tendency and high-end exposure estimates,
respectively. EPA has not identified data on potential ONU inhalation exposures from methylene
chloride waste handling, disposal, treatment and recycling. ONU inhalation exposures are
expected to be lower than worker inhalation exposures however the relative exposure of ONUs
to workers cannot be quantified as described in more detail above in Section 2.4.1.2.20. EPA
calculated risk estimates assuming ONU exposures could be as high as worker exposures as a
Page 376 of 753

-------
high-end estimate and there is large uncertainty in this assumption. Considering the overall
strengths and limitations of the data, EPA's overall confidence in the occupational inhalation
estimates in this scenario is medium to low. Section 2.4.1.2.20 describes the justification for this
occupational scenario confidence rating. The studies that support the health concerns of acute
CNS effects, liver toxicity and cancer and the hazard value and benchmark MOEs are described
above in Section 4.3.1 Risk Estimation Approach and overall EPA has medium confidence in the
acute, chronic and cancer endpoints. Section 3.2.5.3 describes the justification for these
confidence levels.
Table 4-22. Risk Estimation for Acute, Non-Cancer Inhalation Exposures for Waste
Handling, Disposal, Treatment, and Recycling		
II IK l ime Period
l.nripoinl = ( NS I'I'lVcl 1
Acule MIX
(111^/111')
I'Aposlll'C I.C\cl
MOI-'.s lor Acu
Worker & OM :
No rcspimlor
Ic l-'.\posiircs
Worker
API- 25'
lienehniiii'k
MOI.
(= lohil
I I)
8-hr
290
High End
3.6
90
30
Central Tendency
124
3092
1	Data from Putz et al. (1979)
2	Exposures to ONUs were not able to be estimated separately from workers.
3	APF 25 and APF 50 are the two lowest APF allowable under OSHA standards for methylene chloride. EPA does
not assume routine use of PPE that would mitigate risk (respirator APF 25) with this condition of use in part because
only supplied air respirators can be used (see section 2.4.1.1). APF 50 not shown based on MOEs at APF 25 are all
greater than the benchmark MOE.
Table 4-23. Risk Estimation for Chronic, Non-Cancer Inhalation Exposures for Waste
Handling, Disposal, Treatment, and Recycling		
I'lnripoini1
Chronic
MIX
img/nr')
l-l\posurc l.c\cl
MOI-'.s for ( hron
Worker & OM :
No respiriilor
c l-'.\posiires
Workers
API- 25'
lieiichniiirk
MOI.
(= loliil
I 1)
Liver Effects
17.2
High End
0.93
23
10
Central Tendency
32
803
1	Data from Nitschke et al. (1988a)
2	Exposures to ONUs were not able to be estimated separately from workers.
3	APF 25 and APF 50 are the two lowest APF allowable under OSHA standards for methylene chloride. EPA does
not assume routine use of PPE that would mitigate risk (respirator APF 25) with this condition of use in part because
only supplied air respirators can be used (see section 2.4.1.1). APF 50 not shown based on MOEs at APF 25 are all
greater than the benchmark MOE.
Page 377 of 753

-------
Table 4-24. Risk Estimation for Chronic, Cancer Inhalation Exposures for Waste
Handling, Disposal, Treatment, and Recycling		
l-lmlpoini. Tumor
T\pes'
11 K
(risk per mii/iir1)
l'l\|)OSIIIV I.C'M'I
( aneer Risk r.slimales
Worker* OM :
No respirator
lienchmark
Cancer Risk
Liver and lung tumors
1.38E-06
High End
5.71E-05
104
Central Tendency
1.29E-06
1 Data from NTP (.1.986)
2	Exposures to ONUs were not able to be estimated separately from workers.
3	APF 25 and APF 50 are the two lowest APF allowable under OSHA standards for methylene chloride. EPA does
not assume routine use of PPE with this condition of use. Cancer risks with APF 25 or APF 50 are not shown based
on cancer risks without respirators are less than the cancer risk benchmark of 10~4.
4.3.2.1.7 Batch Open-Top Vapor Degreasing
Estimates of MOEs for acute and chronic exposures and cancer risks from inhalation for batch
open-top vapor degreasing are presented Table 4-25, Table 4-26, and Table 4-27, respectively.
For batch open-top vapor degreasing exposure estimates for TWAs of 8 hrs are available based
on modeling with a near-field and far-field approach. EPA calculated 50th and 95th percentiles to
characterize the central tendency and high-end exposure estimates, respectively. EPA used the
near-field air concentrations for worker exposures and the far-field air concentrations for
potential ONU inhalation exposures from methylene chloride batch open-top vapor degreasing as
described in more detail above in Section 2.4.1.2.5. Considering the overall strengths and
limitations of the data, EPA's overall confidence in the occupational inhalation estimates in this
scenario is medium to low. Section 2.4.1.2.5 describes the justification for this occupational
scenario confidence rating. The studies that support the health concerns of acute CNS effects,
liver toxicity and cancer and the hazard value and benchmark MOEs are described above in
Section 4.3.1 Risk Estimation Approach and overall EPA has medium confidence in the acute,
chronic and cancer endpoints. Section 3.2.5.3 describes the justification for these confidence
levels.
Table 4-25. Risk Estimation for Acute, Non-Cancer Inhalation Exposures for Batch Open-
Top Vapor Degreasing	
IIl ( l ime Period
I'lmlpoini = ( NS
1! Heels'
Aeule
MIX
(nig/m ')
l-lxposure
l.e\el
No resp
W orkers
MO
iralor
ONI s
!s for Aeul
API
W orkers
I'lxposil
25:
ONI s
res
API-
Workers
*0:
ONI s
lienehmark
MOI.
(= loial I 1)
8-hr
290
High End
0.39
0.64
9.7
N/A
19
N/A
30
Central
Tendency
1.7
3
43
N/A
86
N/A
1	Data from Putz et al. (1979)
2	APF 25 and APF 50 are the two lowest APF allowable under OSHA standards for methylene chloride and are
considered plausible for respirator use.
N/A = not assessed because ONUs are not assumed to be wearing PPE
Page 378 of 753

-------
Table 4-26. Risk Estimation for Chronic, Non-Cancer Inhalation Exposures for Batch
Open-Top Vapor Degreasing	
limlpoinl1
('limine
lll(
inig/iir')
l-lxposnre
1 .e\ el
Workers
No respiralor
MOI
OM s
No
respiralor
Is lor Cliroi
\\ orkers
API- 25:
lie l-'.\posnrc
ONI s
API- 25:
s
Workers
API- 50-
ONI s
API- 50-
licnchmark
MOI.
(= lohil
I 1)
Liver
Effects
17.2
iiigh i:nd
0.10
0.2
2.5
\ \
5.1
\ \
10
Central
Tendency
0.45
0.87
11
N/A
22
N/A
1	Data from Nitschke et al. (.1.98831
2	APF 25 and APF 50 are the two lowest APF allowable under OSHA standards for methylene chloride and are
considered plausible for respirator use.
N/A = not assessed because ONUs are not assumed to be wearing PPE
Table 4-27. Risk Estimation for Chronic, Cancer Inhalation Exposures for Batch Open-
Top Vapor Degreasing 		
I'lmlpoini. Tumor
Tjpes"
11 K
(risk per
inti/mi)
l'l\pnsiirc
1 .e\ el
W orkers
No respirator
"anccr Risk l-'.siii
ONI s
No rcspiralor
link's
W orkers
API- 25;
ONI s
API- 25;
licnchmark
Cancer Risk
Liver and lung
tumors
1.38E-06
High End
5.27E-04
3.22E-04
2.11E-05
N/A
104
Central
Tendency
9.23E-05
4.74E-05
3.69E-06
N/A
1	Data from NTP (1986)
2	APF 25 and APF 50 are the two lowest APF allowable under OSHA standards for methylene chloride and are
considered plausible for respirator use. APF 50 not shown based on cancer risks at APF 25 are all less than the
cancer risk benchmark of 10~4.
N/A = not assessed because ONUs are not assumed to be wearing PPE
4.3.2.1.8 Conveyorized Vapor Degreasing
Estimates of MOEs for acute and chronic exposures and cancer risks from inhalation for
conveyorized vapor degreasing are presented in Table 4-28, Table 4-29, and Table 4-30,
respectively. For conveyorized vapor degreasing exposure estimates for TWAs of 8 hrs are
available based on modeling with a near-field and far-field approach. EPA calculated 50th and
95th percentiles to characterize the central tendency and high-end exposure estimates,
respectively. EPA used the near-field air concentrations for worker exposures and the far-field
air concentrations for potential ONU inhalation exposures from methylene chloride conveyorized
vapor degreasing as described in more detail above in Section 2.4.1.2.6. Considering the overall
strengths and limitations of the data, EPA's overall confidence in the occupational inhalation
estimates in this scenario is medium to low. Section 2.4.1.2.6 describes the justification for this
occupational scenario confidence rating. The studies that support the health concerns of acute
CNS effects, liver toxicity and cancer and the hazard value and benchmark MOEs are described
above in Section 4.3.1 Risk Estimation Approach and overall EPA has medium confidence in the
acute, chronic and cancer endpoints. Section 3.2.5.3 describes the justification for these
confidence levels.
Page 379 of 753

-------
Table 4-28. Risk Estimation for Acute, Non-Cancer Inhalation Exposures for Conveyorized
Vapor Degreasing				
MIX Time
Period
llnripoint = CNS
11 llccts1
Acute
MIX
(ing/m M
l'l\poslll'C
l.c\cl
M
\\ orkcrs
No respirator
Ol'.s for Acute I".
OM s
No rcspirator
vposnrcs
\\ orkcrs
API- 50-
ONI s
API-50=
licnchmark
MOI.
l= Total I I )
8-hr
290
High End
0.21
0.32
10.4
N/A
30
Central
Tendency
0.60
1
30
N/A
1	Data from Putz et al. (1979)
2	APF 25 and APF 50 are the two lowest APF allowable under OSHA standards for methylene chloride and are
considered plausible for respirator use.
N/A = not assessed because ONUs are not assumed to be wearing PPE
Table 4-29. Risk Estimation for Chronic, Non-Cancer Inhalation Exposures for
Conveyorized Vapor Degreasing 	
I'lnripoini1
Chronic
MIX
(iiiii/nr1)
l-lxpoMirc
l.c\cl
MO
Workers
No respirator
lis lor Chronic 1
ONI s
No respirator
.\posii res
Workers
API- 50-
ONI s
API-
50-
licnchmark
MOM
(= Total
I 1)
Liver Effects
17.2
High End
0.05
0.1
2.7
N/A
10
Central
Tendency
0.15
0.30
7.7
N/A
1	Data from Nitschke et al. (1988a")
2	APF 25 and APF 50 are the two lowest APF allowable under OSHA standards for methylene chloride and are
considered plausible for respirator use.
N/A = not assessed because ONUs are not assumed to be wearing PPE
Table 4-30. Risk Estimation for Chronic, Cancer Inhalation Exposures for Conveyorized
Vapor Degreasing			
I'lnripoini. Tumor
Tjpes"
II R
(risk per
msi/m')
l'l\posnre
1 .c\ el
W orkcrs
No respirator
"anccr Risk l-lstii
ONI s
No respirator
nates
W orkcrs
API- 25;
ONI s
API- 25:
licnchmark
Cancer Risk
Liver and lung
tumors
1.38E-06
High End
9.87E-04
6.37E-04
2.97E-05
N/A
104
Central
Tendency
2.67E-04
1.39E-04
1.04E-05
N/A
1	Data from NTP (.1.986)
2	APF 25 and APF 50 are the two lowest APF allowable under OSHA standards for methylene chloride and are
considered plausible for respirator use.
N/A = not assessed because ONUs are not assumed to be wearing PPE
Page 380 of 753

-------
4.3.2.1.9 Cold Cleaning
Estimates of MOEs for acute and chronic exposures and cancer risks from inhalation for cold
cleaning are presented in Table 4-31, Table 4-32, and Table 4-33, respectively. For cold cleaning
exposure estimates for TWAs of 8 hrs are available based on personal monitoring data samples,
including a range of values from 1 source (T	;). EPA calculated 50th and 95th
percentiles to characterize the central tendency and high-end exposure estimates, respectively.
EPA has not identified data on potential ONU inhalation exposures from methylene chloride
cold cleaning. ONU inhalation exposures are expected to be lower than worker inhalation
exposures however the relative exposure of ONUs to workers cannot be quantified as described
in more detail above in Section 2.4.1.2.7. EPA calculated risk estimates assuming ONU
exposures could be as high as worker exposures as a high-end estimate and there is large
uncertainty in this assumption. Considering the overall strengths and limitations of the data,
EPA's overall confidence in the occupational inhalation estimates in this scenario is medium to
low. Section 2.4.1.2.7 describes the justification for this occupational scenario confidence rating.
The studies that support the health concerns of acute CNS effects, liver toxicity and cancer and
the hazard value and benchmark MOEs are described above in Section 4.3.1 Risk Estimation
Approach and overall EPA has medium confidence in the acute, chronic and cancer endpoints.
Section 3.2.5.3 describes the justification for these confidence levels.
Table 4-31. Risk Estimation for Acute, Non-Cancer Inhalation Exposures for Cold
Cleaning				
MIX l ime Period
l.mlpoinl = ( \s
i: riccis1
Acute
HEC
(inii/in1)
Exposure
l.e\el
MOEs It
Worker & OM :
No rcspimlor
>r Aculc Expo
W orker
API- 25'
in res
W orker
API- 50'
lienchniiii'k
MOI.
(= Toliil I 1)
8-hr
290
High End
0.29
7.3
15
30
Central
Tendency
1.04
26
52
1	Data from Putz et al. (1979)
2	Exposures to ONUs were not able to be estimated separately from workers.
3	APF 25 and APF 50 are the two lowest APF allowable under OSHA standards for methylene chloride and are
considered plausible for respirator use.
Table 4-32. Risk Estimation for Chronic, Non-Cancer Inhalation Exposures for Cold
Cleaning
Enilpoinl1
Chronic
MIX
(niii/m M
Exposure
1 .e\ el
MOEs It
Worker & OM :
No rcspir;ilor
r Chronic Ex
Worker
API- 25'
)osurcs
Worker
API- 50s
Bench in iii'k
MOI.
(= Toliil
I 1)
Liver Effects
17.2
High End
0.08
1.9
3.8
10
Central
Tendency
0.27
7
13
1 Data from Nitschke et al. (1988a)
9
Exposures to ONUs were not able to be estimated separately from workers.
3 APF 25 and APF 50 are the two lowest APF allowable under OSHA standards for methylene chloride and are
considered plausible for respirator use.
Page 381 of 753

-------
Table 4-33. Risk Estimation for Chronic, Cancer Inhalation Exposures for Cold Cleaning
l-lmlpoinl. Tumor
Tjpes"
11 K
(risk per
infi/m')
l'l\posurc
l.c\cl
Cancel
Worker & <>\l :
No respirator
Risk I'.sliina
Worker
API- 25'
es
Worker
API- 50'
benchmark
Cancer Risk
Liver and lung
tumors
1.38E-06
High End
7.08E-04
2.83E-05
1.42E-05
104
Central
Tendency
1.54E-04
6.14E-06
3.07E-06
1 Data from NTP (1986)
9
Exposures to ONUs were not able to be estimated separately from workers.
3 APF 25 and APF 50 are the two lowest APF allowable under OSHA standards for methylene chloride and are
considered plausible for respirator use.
4.3.2.1.10 Commercial Aerosol Products (Aerosol Degreasing, Aerosol
Lubricants, Automotive Care Products)
Estimates of MOEs for acute and chronic exposures and cancer risks from inhalation for
commercial aerosol products are presented in Table 4-34, Table 4-35, and Table 4-36,
respectively. For commercial aerosol products exposure estimates for TWAs of 8 hrs are
available based on personal monitoring data samples, including 21 data points from (Finkel.
2017V EPA calculated 50th and 95th percentiles to characterize the central tendency and high-end
exposure estimates, respectively. Considering the overall strengths and limitations of the data,
EPA's overall confidence in the occupational inhalation estimates in this scenario is medium.
Section 2.4.1.2.8 describes the justification for this occupational scenario confidence rating. The
studies that support the health concerns of acute CNS effects, liver toxicity and cancer and the
hazard value and benchmark MOEs are described above in Section 4.3.1 Risk Estimation
Approach and overall EPA has medium confidence in the acute, chronic and cancer endpoints.
Section 3.2.5.3 describes the justification for these confidence levels.
Table 4-34. Risk Estimation for Acute, Non-Cancer Inhalation Exposures for Commercial
Aerosol Products (Aerosol Degreasing, Aerosol Lubricants, Automotive Care Products)
lll-'.C Time
Period
I'lmlpoini =
C\S I!Heels'
Acme
III C
(inii/mi)
l-lxposurc
1 .c\ el
MOI'.s lor Aciilc
Workers ami OM s
No respirator
l-'.\posiircs
Workers
API- 25:
licnchmark
MOI.
(= loial I 1)
8-hr
290
High End
1.3
32
30
Central
Tendency
48
1201
1	Data from Putz et al. (1979)
2	APF 25 and APF 50 are the two lowest APF allowable under OSHA standards for methylene chloride. EPA does
not assume routine use of PPE that would mitigate risk (respirator APF 25) with this condition of use in part because
only supplied air respirators can be used (see section 2.4.1.1). APF 50 not shown based onMOEs at APF 25 are all
greater than the benchmark MOE.
Page 382 of 753

-------
Table 4-35. Risk Estimation for Chronic, Non-Cancer Inhalation Exposures for
Commercial Aerosol Products (Aerosol Degreasing, Aerosol Lubricants, Automotive Care
Products) 			i	
linripoinl1
('limine
MIX
(inii/in1)
Exposure
1 .c\ el
MOI-'.s
Workers and
ONI
No rcspiraloi"
lor Chronic l-'.\pos
Workers
API- 25'
ii res
Workers API-
5111
licnchmark
MOI.
(= Tolal
I 1)
Liver Effects
17.2
High End
0.33
8.3
17
10
Central
Tendency
12
312
625
1	Data from Nitschke et al. (198831
2	Exposures to ONUs were not able to be estimated separately from workers.
3	APF 25 and APF 50 are the two lowest APF allowable under OSHA standards for methylene chloride and are
considered plausible for respirator use.
Table 4-36. Risk Estimation for Chronic, Cancer Inhalation Exposures for Commercial
Aerosol Products (Aerosol De
greasing, Aeroso
Lubricants, Automotive Care Products)
r.ndpoini. Tumor
Tjpes"
11 K
(risk per
mg/nr')
l-lxposnrc l.c\cl
('.nicer Risk I-'.
W orkcrs and ON I s
No rcspiraloi"
siimales
W orkcrs
API- 25'
licnchmark
Cancer Risk
Liver and lung
tumors
1.38E-06
High End
1.61E-04
6.44E-06
104
Central Tendency
3.31E-06
1.32E-07
1	Data from NTP (1986)
2	Exposures to ONUs were not able to be estimated separately from workers.
3	APF 25 and APF 50 are the two lowest APF allowable under OSHA standards for methylene chloride. EPA does
not assume routine use of PPE that would mitigate risk (respirator APF 25) with this condition of use in part because
only supplied air respirators can be used (see section 2.4.1.1). APF 50 not shown based on MOEs at APF 25 are all
greater than the benchmark MOE.
4.3.2.1.11 Adhesives and Sealants
Estimates of MOEs for acute and chronic exposures and cancer risks from inhalation for
adhesives and sealants are presented in Table 4-37, Table 4-38, and Table 4-39, respectively. For
both spray and non-spray industrial adhesive application exposure estimates for TWAs of 15
mins, and 8 hrs are available based on personal monitoring data samples, including 100 data
points for non-spray adhesive use (NIOSIL 1085); (EPA. 1985). 16 data points for spray
adhesive use from multiple data sources (i	M s f ). (WHO. 1996b). (T'P \ 1985). and
468 personal monitoring samples for unknown application (Finkel. 2017). The 15 mins TWAs
are useful for characterizing exposures shorter than 8 hrs that could lead to adverse CNS effects.
PODs specific to 15 mins TWA exposures were used for characterization of the risk. EPA
calculated 50th and 95th percentiles to characterize the central tendency and high-end exposure
estimates, respectively. EPA has not identified data on potential ONU inhalation exposures from
methylene chloride adhesives and sealants. ONU inhalation exposures are expected to be lower
than worker inhalation exposures however the relative exposure of ONUs to workers cannot be
quantified as described in more detail above in Section 2.4.1.2.9. EPA calculated risk estimates
Page 383 of 753

-------
assuming ONU exposures could be as high as worker exposures as a high-end estimate and there
is large uncertainty in this assumption. Considering the overall strengths and limitations of the
data, EPA's overall confidence in the occupational inhalation estimates in this scenario is
medium. Section 2.4.1.2.9 describes the justification for this occupational scenario confidence
rating. The studies that support the health concerns of acute CNS effects, liver toxicity and
cancer, the respective hazard values and benchmark MOEs are described above in Section 4.3.1
Risk Estimation Approach. Overall EPA has medium confidence in the acute, chronic and cancer
hazard endpoints. Section 3.2.5.3 describes the justification for these confidence levels.
Table 4-37. Risk Estimation for Acute, Non-Cancer Inhalation Exposures for Adhesives
and Sealants
lll'X Time Period
l.mlpoim = CNS
r.nwis1
Acuk'
MIX
img/nr')
l'l\|)UMIIV
l.e\el
moi-'.s r<
Worker & OM :
No rcspimlor
i' Acuk' l-l\|)o
\\ orker
API- 25'
sii res
Worker
API 50*
lienehniiii'k
MOI.
(= lohil
1 1 )
SPRAY USES
8-hr
290
High End
0.52
13
26
30
Central
Tendency
7.4
186
372
15-min
1706
High End
2.6
64
129
30
Central
Tendency
6.0
150
299
NON-SPRAY USES
8-hr
290
High End
0.98
25
49
30
Central
Tendency
28
692
1385
15-min
1706
High End
3.0
75
150
30
Central
Tendency
3.4
86
172
UNKNOWN APPLICATION
8-hr
290
High End
0.42
11
21
30
Central
Tendency
10.7
267
533
1 Data from Putz et al. (1979)
2	Exposures to ONUs were not able to be estimated separately from workers; also, this scenario covers a broad range
of industries and processes, which may result in significant differences between central and high-end exposures.
3	APF 25 and APF 50 are the two lowest APF allowable under OSHA standards for methylene chloride and are
considered plausible for respirator use.
Page 384 of 753

-------
Table 4-38. Risk Estimation for Chronic, Non-Cancer Inhalation Exposures for Adhesives
and Sealants
l-'.nd ixiiiil1
( hronic
MIX
(mii/iii"4)
l-lxposure
1 .e\ el
MOI-'.s loi
Worker* OM :
No respirsilor
Chronic l'.\p
W orker
API- 25'
isii res
Worker
API- 50'
licnchmsirk
MOI.
(= Tolsil
I 1)
SPRAY USES
Liver Effects
17.2
High End
0.14
3.38
6.8
10
Central
Tendency
1.93
48
97
NON-SPRAY USES
Liver Effects
17.2
High End
0.25
6.4
13
10
Central
Tendency
7.2
180
360
UNKNOWN APPLICATION
Liver Effects
17.2
High End
0.11
2.7
5.5
10
Central
Tendency
2.8
69
139
1	Data from Nitschke et al. (1988a)
2	Exposures to ONUs were not able to be estimated separately from workers.
3	APF 25 and APF 50 are the two lowest APF allowable under OSHA standards for methylene chloride and are
considered plausible for respirator use.
Table 4-39. Risk Estimation for Chronic, Cancer Inhalation Exposures for Adhesives and
Sealants
l-lmlpoiiil. Tumor
Tjpes"
11 K
(risk per
msi/iii')
Exposure
1 .e\ el
('si lie
Worker* OM :
No respirsilor
it Risk I'.slinisil
Worker
API 25'
;s
W orker
API- 51 r
licnchmsirk
SPRAY
Cancer Risk
Liver and lung
tumors
1.38E-06
High End
3.95E-04
1.58E-05
7.90E-6
104
Central
Tendency
2.14E-05
8.56E-07
4.28E-7
NON-SPRAY
Cancer Risk
Liver and lung
tumors
1.38E-06
High End
2.10E-04
8.37E-06
4.18E-6
104
Central
Tendency
5.74E-06
2.30E-07
1.15E-7
UNKNOWN APPLICATION
Cancer Risk
Liver and lung
tumors
1.38E-06
High End
4.88E-04
1.95E-05
9.75E-06
104
Central
Tendency
1.49E-05
5.97E-07
2.98E-07
1 Data from NTP (1986)
9
Exposures to ONUs were not able to be estimated separately from workers.
3 APF 25 and APF 50 are the two lowest APF allowable under OSHA standards for methylene chloride and are
considered plausible for respirator use.
Page 385 of 753

-------
4.3.2.1.12 Paints and Coatings
Risk estimates for methylene chloride-based paint and coating removers were assessed in EPA's
2014 Risk Assessment on Paint Stripping Use for Methylene Chloride (	) and
those results are included in Appendix L. Risk estimates for use of methylene chloride-based
paints and coatings are described in this section.
Estimates of MOEs for acute and chronic exposures and cancer risks from inhalation for paints
and coatings are presented in Table 4-40, Table 4-41, and Table 4-42, respectively. For paints
and coatings exposure estimates for TWAs of 8 hrs are available based on personal monitoring
data samples, including 27 data points from 2 sources (OS!	), (EPA. 1985) and 271 data
points from two sources (Finkel. 2017); Defense Occupational and Environmental Health
Readiness System - Industrial Hygiene (DOEHRS-IH) (2018). For paint and coating removers,
exposure estimates for TWAs of 8 hrs are available from EPA's 2014 Risk Assessment on Paint
Stripping Use for Methylene Chloride (	014) and from DoD (Defense Occupational
and Environmental Health Readiness System. - Industrial Hygiene (DOEHRS-IH). 2018). The
DoD data also included 15-min TWAs and these 15 mins TWAs are useful for characterizing
exposures shorter than 8 hrs that could lead to adverse CNS effects. PODs specific to 15 mins
TWA exposures were used for characterization of the risk. EPA calculated 50th and 95th
percentiles to characterize the central tendency and high-end exposure estimates, respectively.
EPA has not identified data on potential ONU inhalation exposures from methylene chloride
paints and coatings. ONU inhalation exposures are expected to be lower than worker inhalation
exposures however the relative exposure of ONUs to workers cannot be quantified as described
in more detail above in Section 2.4.1.2.10. EPA calculated risk estimates assuming ONU
exposures could be as high as worker exposures as a high-end estimate and there is large
uncertainty in this assumption. Considering the overall strengths and limitations of the data,
EPA's overall confidence in the occupational inhalation estimates in this scenario is medium to
high. Section 2.4.1.2.10 describes the justification for this occupational scenario confidence
rating. The studies that support the health concerns of acute CNS effects, liver toxicity and
cancer and the hazard value and benchmark MOEs are described above in Section 4.3.1 Risk
Estimation Approach and overall EPA has medium confidence in the acute, chronic and cancer
endpoints. Section 3.2.5.3 describes the justification for these confidence levels.
Table 4-40. Risk Estimation for Acute, Non-Cancer Inhalation Exposures for Paints and
Coatings Including Commercial Paint and Coating Removers	i	
MIX lime Period
l.ndpoim = ( NS
l-'.ITecls1 / r.\|)
-------
MIX lime Period
l.ndpoinl = ( NS
I-'. Heels' / r.\|)
-------
3	APF 25 and APF 50 are the two lowest APF allowable under OSHA standards for methylene chloride. EPA does
not assume routine use of PPE that would mitigate risk (respirator APF 25 or 50) with this condition of use.
4	See Appendix L for the description of exposure and risk estimates
5	High-End is the "High" exposure estimate and central tendency is the "midpoint" exposure estimate as described in
the 2014 assessment there are not sufficient data to calculate a 50th and 95th percentile for more information see
Appendix L and Table L-6.
6	While the benchmark used in the 2014 assessment was 60 the benchmark shown here is 30 for consistency with
this current evaluation.
7	Exposure data were not available to characterize the central tendency and high-end exposures.
Table 4-41. Risk Estimation for Chronic, Non-Cancer Inhalation Exposures for Paints and
Coatings				i	
l.i\er l-'.ITecls l.nripninl
/ I'1\|)osiiiv Scenario1
('limine
MIX
(ing/inM
I'lxposure
1 .e\ el
MOI-'.s l
Worker
OM :
No respirator
r Chronic 11 \
Worker
API- 25'
[insures
W nrker
API- 50'
licnchmark
MOF.
(= Tnlal
I 1)
Paints and Coatings
Paints and Coatings
17.2
High End
0.21
5.2
10.3
10
Central
Tendency
1.08
27
54
Paints and Coatings (Unknown Application)
Paints and Coatings
17.2
High End
0.29
7.2
14
10
Central
Tendency
6.1
152
505
Paint and Coating Removers 4
Professional
Contractors
17.2
High End5
0.025
1
2
10
Central
Tendency5
0.05
1
2
Automotive
Refinishing
17.2
High End5
0.2
5
10
10
Central
Tendency5
0.3
7
14
Furniture Refinishing
17.2
High End5
0.03
0.8
1.6
10
Central
Tendency5
0.1
2
4
10
Art Restoration and
Conservation
17.2
Point estimate6
34
860
1720
10
Aircraft Paint
Stripping
17.2
High End5
0.02
0.5
1
10
Central
Tendency5
0.04
1
2
Graffiti Removal
17.2
High End5
0.1
2
4
10
Central
Tendency5
0.1
3
6
Non-Specific
17.2
High End5
0.01
0.3
0.6
10
Page 388 of 753

-------
l.i\er l-'.ITccls l.ndpoini
/ l-Aposurc Scenario1
Workplace Settings
- Immersion
Stripping of Wood
Chronic
MIX
(mg/m M
I'Aposurc
1 .c\ el
MOI-'.s l
Worker K:
OM :
No respirator
ii' Chronic L\
Worker
API- 25'
leisures
W orker
API 50'
Benchmark
MOI.
(= Toial
I I)
Central
Tendency5
0.02
0.5
1
Non-Specific
Workplace Settings -
Immersion Stripping
of Wood and Metal
17.2
High End5
0.07
2
4
10
Central
Tendency5
0.1
2
4
Non-Specific
Workplace Settings
- Unknown
17.2
High End5
0.18
4
8
10
Central
Tendency5
0.21
5
10
DoD Paint Removal
17.2
High End
1.6
40
80
10
Central
Tendency
15
379
757
1	Data from Nitschke et al. (.1.988a)
2	Exposures to ONUs were not able to be estimated separately from workers.
3	APF 25 and APF 50 are the two lowest APF allowable under OSHA standards for methylene chloride. EPA does
not assume routine use of PPE that would mitigate risk (respirator APF 25) with this condition of use in part because
only supplied air respirators can be used (see section 2.4.1.1). ONUs are not expected to wear respirators.
4	See Appendix L for the description of exposure and risk estimates
5	High-End is the "High" exposure estimate and central tendency is the "midpoint" exposure estimate shown in
Appendix L Tables 3-21 through 3-29
6	Exposure data were not available to characterize the central tendency and high-end exposures.
Table 4-42. Risk Estimation for Chronic, Cancer Inhalation Exposures for Paints and
Coatings				
Cancel' Risk
Liter and lung
1 ii mors1 / I'lxpoMirc
Scenario
11 K
(risk per
mg/m M
l''.\posure Let el
('.nicer
Worker & OM :
No respiralor
tisk I'Mimale
W orker
API- 25'
s
Worker
API- 50'
Benchmark
Paints and Coatings (Spray)
Paints and
Coatings
1.38E-06
High End
2.58E-04
1.03E-05
5.16E-6
104
Central Tendency
3.83E-05
1.53E-06
7.66E-7
Paints and Coatings (Unknown Application)
Paints and
Coatings
1.38E-06
High End
1.85E-04
7.40E-06
3.70E-06
104
Central Tendency
6.76E-06
2.7E-07
1.35E-07
Paint and Coating Removers 4

1E-05 5
High End6
3.9E-3
1.6E-4
8.0E-5
104
Page 389 of 753

-------
( anccr Risk
l.i\cr iiiul lung
minors' / I'1\|)omiiv
Scenario
Professional
Contractors
11 K
(risk pei'
mg/niM
l-lxpoMirc l.c\cl
('.nicer
Worker* OM :
No respiralor
iisk IslininK
W orker
API- 25'
s
Worker
API- 50'
liciichmark
Central Tendency6
2.0E-3
7.9E-5
4.0E-5
Automotive
Refinishing
1E-05 5
High End6
5.4E-4
2.2E-5
1.1E-5
104
Central Tendency6
3.3E-4
1.3E-5
6.5E-6
Furniture
Refinishing
1E-05 5
High End6
2.9E-3
1.2E-4
6.0E-5
104
Central Tendency6
1.5E-3
5.9E-5
3.0E-5
104
Art Restoration
and Conservation
1E-05 5
Point estimate7



104
Aircraft Paint
Stripping
1E-05 5
High End6
5.0E-3
2.0E-4
1.0E-4
104
Central Tendency6
2.5E-3
1.0E-4
5.0E-5
Graffiti Removal
1E-05 5
High End6
1.6E-3
6.2E-5
3.1E-5
104
Central Tendency6
7.9E-4
3.2E-5
1.6E-5
Non-Specific
Workplace Settings
- Immersion
Stripping of Wood
1E-05 5
High End6
9.1E-3
3.7E-4
1.9E-4
104
Central Tendency6
4.6E-3
1.8E-4
9.0E-5
Non-Specific
Workplace Settings
- Immersion
Stripping of Wood
and Metal
1E-05 5
High End6
1.3E-3
5.3E-5
2.7E-5
104
Central Tendency6
1.1E-3
4.3E-5
2.2E-5
Non-Specific
Workplace Settings
- Unknown
1E-05 5
High End6
5.6E-4
2.2E-5
1.1E-5
104
Central Tendency6
4.7E-4
1.9E-5
1.0E-5
1 Data from NTP (.1.986)
9
Exposures to ONUs were not able to be estimated separately from workers.
3	APF 25 and APF 50 are the two lowest APF allowable under OSHA standards for methylene chloride. EPA does
not assume routine use of PPE that would mitigate risk (respirator APF 25) with this condition of use in part because
only supplied air respirators can be used (see section 2.4.1.1).
4	See Appendix L for the description of exposure and risk estimates.
5	The IUR used in the 2014 assessment was derived assuming 24 hr/day, 7 day/week exposure and the air
concentration exposure estimates were adjusted accordingly. The results of these calculations are shown in this table
and described in Appendix L. The IUR used in this evaluation was derived assuming worker exposures of 8 hrs/day,
5	days/week exposure and the air concentration exposure estimates were adjusted accordingly.
6	High-End is the "High" exposure estimate and central tendency is the "midpoint" exposure estimate shown in
Appendix L Tables 3-12 through 3-20
7	Exposure data were not available to characterize the central tendency and high-end exposures.
4.3.2.1.13 Adhesive and Caulk Removers
Estimates of MOEs for acute and chronic exposures and cancer risks from inhalation for
adhesive and caulk removers are presented in Table 4-43, Table 4-44, and Table 4-45,
Page 390 of 753

-------
respectively. EPA did not find specific industry information exposure data for adhesive and
caulk removers, based on expected worker activities, EPA assumes that the use of adhesive and
caulk removers is similar to paint stripping by professional contractors and used the air
concentration data from the 2014 Risk Assessment on Paint Stripping Use for Methylene
Chloride (	) where overall, four personal monitoring data samples were available.
EPA calculated the 50th and 95th percentile 8-hr TWA concentrations to represent a central
tendency and high-end estimate of potential occupational inhalation exposures, respectively.
EPA has not identified data on potential ONU inhalation exposures from methylene chloride
adhesive and caulk removers. ONU inhalation exposures are expected to be lower than worker
inhalation exposures however the relative exposure of ONUs to workers cannot be quantified as
described in more detail above in Section 2.4.1.2.11. EPA calculated risk estimates assuming
ONU exposures could be as high as worker exposures as a high-end estimate and there is large
uncertainty in this assumption. Considering the overall strengths and limitations of the data,
EPA's overall confidence in the occupational inhalation estimates in this scenario is medium.
Section 2.4.1.2.11 describes the justification for this occupational scenario confidence rating.
The studies that support the health concerns of acute CNS effects, liver toxicity and cancer and
the hazard value and benchmark MOEs are described above in Section 4.3.1 Risk Estimation
Approach and overall EPA has medium confidence in the acute, chronic and cancer endpoints.
Section 3.2.5.3 describes the justification for these confidence levels.
The high-end short-term exposure identified in Section 2.4.1.2.11 (14,000 mg/m3) exceeds the
NIOSH IDLH value of 7981 mg/m3 fNIOSH. 1994) described in Section 3.2.3.1.1. The short-
term value identified in Section 2.4.1.2.11 (7100 mg/m3) approaches the IDLH value. The
NIOSH IDLH value was set to avoid situations that are immediately dangerous and is a value
above which individuals should not be exposed for any length of time.
Table 4-43. Risk Estimation for Acute, Non-Cancer Inhalation Exposures for Adhesive and
Caulk Removers
MIX Time
Period
Fndpoinl = CNS
Fffccls1
Acme lil t
(niii/mM
Fxposnrc
1 .c\ el
MOF.s
Worker* OM :
No rcspii'iilor
for Acute F\pos
W orkcr
API 25'
ii res
W orkcr
APF 50s
licnchniiirk
MOF
(= loliil
I I)
8-hr


High End
0.10
2.4
4.9
30
290
Central
Tendency
0.19
4.8
9.5
1	Data from Putz et al. (1979)
2	Exposures to ONUs were not able to be estimated separately from workers.
3	APF 25 and APF 50 are the two lowest APF allowable under OSHA standards for methylene chloride and are
considered plausible for respirator use.
Table 4-44. Risk Estimation for Chronic, Non-Cancer Inhalation Exposures for Adhesive
and Caulk Removers
Fndpoinl'
Chronic
MIX
(inii/in1)
Fxposnrc
1 .e\ el
MOF.s 1
Worker* OM :
No rcspimlor
ii' Chronic F\po
Worker
APF 25'
sii res
W orkcr
APF 50'
licnchniiirk
MOF
(= To(;il
I I)
Liver Effects
17.2
High End
0.03
0.63
1.3
10
Page 391 of 753

-------


Central
0.05
1.2
2.5



Tendency

1	Data from Nitschke et al. (1988a)
2	Exposures to ONUs were not able to be estimated separately from workers.
3	APF 25 and APF 50 are the two lowest APF allowable under OSHA standards for methylene chloride and are
considered plausible for respirator use.
Table 4-45. Risk Estimation for Chronic, Cancer Inhalation Exposures for Adhesive and
Caulk Removers
r.nripoinl. Tumor
T\ pes4
11 R
(risk per
m Si/m M
l'l\posuiv
l.c\cl
Cancer Risk
Worker & OM :
No rcspiralor
'.slimales Cai
Worker
API- 25'1
icei- Risk
W orkcr
API- 50'
licnchmark
Cancer Risk
Liver and lung
tumors
1.38E-06
High End
2.11E-03
8.44E-05
4.22E-05
104
Central
Tendency
8.34E-04
3.33E-05
1.67E-05
1 Data from NTP (1986)
9
Exposures to ONUs were not able to be estimated separately from workers.
3 APF 25 and APF 50 are the two lowest APF allowable under OSHA standards for methylene chloride and are
considered plausible for respirator use.
Overall, there is medium confidence in the exposure and hazard estimates that make up the risk
estimates and the risk estimates for acute, chronic and cancer all indicate human health hazard
concerns and acute and chronic non-cancer concerns even when an APF 50 respirator is used.
4.3.2.1.14 Miscellaneous Non-Aerosol Commercial and Industrial Uses
Estimates of MOEs for acute and chronic exposures and cancer risks from inhalation for
miscellaneous non-aerosol industrial and commercial settings are presented in Table 4-46, Table
4-47, and Table 4-48, respectively. For miscellaneous non-aerosol industrial and commercial
settings exposure estimates for TWAs of 8 hrs are available based on personal monitoring data
samples, including 108 data points from 1 source (	85). EPA calculated 50th and 95th
percentiles to characterize the central tendency and high-end exposure estimates, respectively.
EPA has not identified data on potential ONU inhalation exposures from methylene chloride
miscellaneous non-aerosol industrial and commercial settings. ONU inhalation exposures are
expected to be lower than worker inhalation exposures however the relative exposure of ONUs
to workers cannot be quantified as described in more detail above in Section 2.4.1.2.19. EPA
calculated risk estimates assuming ONU exposures could be as high as worker exposures as a
high-end estimate and there is large uncertainty in this assumption. Considering the overall
strengths and limitations of the data, EPA's overall confidence in the occupational inhalation
estimates in this scenario is medium. Section 2.4.1.2.19 describes the justification for this
occupational scenario confidence rating. The studies that support the health concerns of acute
CNS effects, liver toxicity and cancer and the hazard value and benchmark MOEs are described
above in Section 4.3.1 Risk Estimation Approach and overall EPA has medium confidence in the
acute, chronic and cancer endpoints. Section 3.2.5.3 describes the justification for these
confidence levels.
Page 392 of 753

-------
Table 4-46. Risk Estimation for Acute, Non-Cancer Inhalation Exposures for Non-Aerosol
Commercial and Industrial Uses
II EC l ime Period
l.nripoinl = CNS
l.nWis1
Anile
MIX
img/nr')
l-'.\posiirc
1 .c\ el
MOI-'.s In
Worker* OM :
No respirator
 Aeule I xpo
W orker
API- 25'
su res
W orker
API- 50'
Benchmark
MOI.
(= lodl
I 1)
8-hr
290
High End
0.31
7.8
16
30
Central
Tendency
5.1
128
256
1	Data from Putz et al. (1979)
2	Exposures to ONUs were not able to be estimated separately from workers; also, this scenario covers a broad range
of industries and processes, which may result in significant differences between central and high-end exposures.
3	APF 25 and APF 50 are the two lowest APF allowable under OSHA standards for methylene chloride and are
considered plausible for respirator use.
Table 4-47. Risk Estimation for Chronic, Non-Cancer Inhalation Exposures for Non-
Aerosol Commercial and Industrial Uses
I'lnripoini1
( hronic
MIX
(in ii/iii")
l-'.\posiirc
1 .c\ el
MOI-'.s for (
Worker* OM :
No respirator
lironie l-'.\j
Worker
API- 25'
)osnres
W orker
API 50'
Benchmark
MOI.
(= loliil
I 1)
Liver Effects
17.2
High End
0.08
2.0
4.0
10
Central
Tendency
1.3
33
66
1	Data from Nitschke et al. (1988a)
2	Exposures to ONUs were not able to be estimated separately from workers; also, this scenario covers a broad range
of industries and processes, which may result in significant differences between central and high-end exposures.
3	APF 25 and APF 50 are the two lowest APF allowable under OSHA standards for methylene chloride and are
considered plausible for respirator use.
Table 4-48. Risk Estimation for Chronic, Cancer Inhalation Exposures for Non-Aerosol
Commercial and Industrial Uses
l-'.nripoinl. Tumor
Tjpes1
11 K
(risk per
111 Si/lll')
Exposure l.c\cl
Cancer Risk I-
Worker* ONI :
No respirator
slimalcs
Worker
API- 25'
Benchmark
Cancer Risk
Liver and lung tumors
1.38E-06
High End
6.58E-04
2.63E-05
104
Central Tendency
3.11E-05
1.24E-06
1 Data from NTP (1986)
9
Exposures to ONUs were not able to be estimated separately from workers; also, this scenario covers a broad range
of industries and processes, which may result in significant differences between central and high-end exposures.
3 APF 25 and APF 50 are the two lowest APF allowable under OSHA standards for methylene chloride and are
considered plausible for respirator use. APF 50 not shown based on cancer risks at APF 25 are all less than the
cancer risk benchmark of 10~4.
Page 393 of 753

-------
4.3.2.1.15 Fabric Finishing
Estimates of MOEs for acute and chronic exposures and cancer risks from inhalation for fabric
finishing are presented in Table 4-49, Table 4-50, and Table 4-51, respectively. For fabric
finishing exposure estimates for TWAs of 8 hrs are available based on personal monitoring data
samples, including 39 data points from two sources OSHA (2.019); (Finkel. 2017). EPA
calculated 50th and 95th percentiles to characterize the central tendency and high-end exposure
estimates, respectively. EPA has not identified data on potential ONU inhalation exposures from
methylene chloride fabric finishing. ONU inhalation exposures are expected to be lower than
worker inhalation exposures however the relative exposure of ONUs to workers cannot be
quantified as described in more detail above in Section 2.4.1.2.12. EPA calculated risk estimates
assuming ONU exposures could be as high as worker exposures as a high-end estimate and there
is large uncertainty in this assumption. Considering the overall strengths and limitations of the
data, EPA's overall confidence in the occupational inhalation estimates in this scenario is
medium to low. Section 2.4.1.2.12 describes the justification for this occupational scenario
confidence rating. The studies that support the health concerns of acute CNS effects, liver
toxicity and cancer and the hazard value and benchmark MOEs are described above in Section
4.3.1 Risk Estimation Approach and overall EPA has medium confidence in the acute, chronic
and cancer endpoints. Section 3.2.5.3 describes the justification for these confidence levels.
Table 4-49. Risk Estimation for Acute, Non-Cancer Inhalation Exposures for Fabric
Finishing				i	
MIX Time Period
l.nripoinl = CNS HITcels1
Anile
MIX
img/nr')
l-lxpoMire l.e\el
MOI-'.s lor Aenlt
Worker & OM :
No respii'iilor
 r.\|)osures
W orker
API- 25'
lienehniiirk MOI.
(= locil I I )
8-hr
290
High End
2.1
53
30
Central Tendency
37
928
1	Data from Putz et al. (1979)
2	Exposures to ONUs were not able to be estimated separately from workers.
3	APF 25 and APF 50 are the two lowest APF allowable under OSHA standards for methylene chloride. EPA does
not assume routine use of PPE that would mitigate risk (respirator APF 25) with this condition of use in part because
only supplied air respirators can be used (see section 2.4.1.1). APF 50 not shown based onMOEs at APF 25 are all
greater than the benchmark MOE.
Table 4-50. Risk Estimation for Chronic, Non-Cancer Inhalation Exposures for Fabric
Finishing				
I'lnripoinl1
Chronic
MIX
(111^/111')
I'lxposiirc l.c\cl
MOI-'.s for ( liroi
W orker & OM :
No respinilor
lie l-'.\posiires
Worker
API- 25'
lienehniiirk
MOI.
(= loliil
I 1)
Liver Effects
17.2
High End
0.56
14
10
Central Tendency
9.6
241
1	Data from Nitschke et al. (1988a)
2	Exposures to ONUs were not able to be estimated separately from workers.
3	APF 25 and APF 50 are the two lowest APF allowable under OSHA standards for methylene chloride. EPA does
not assume routine use of PPE that would mitigate risk (respirator APF 25) with this condition of use in part because
Page 394 of 753

-------
only supplied air respirators can be used (see section 2.4.1.1). APF 50 not shown based onMOEs at APF 25 are all
greater than the benchmark MOE.
Table 4-51. Risk Estimation for Chronic, Cancer Inhalation Exposures for Fabric
Finishing				
I'lmlpoini. Tumor
Tjpes"
11 K
(risk per
111 Si/lll1)
Kxposurc l.c\cl
Cancer Risk I-
Worker* OM :
No respirator
slimalcs
Worker
API 25'
licnchmark
Cancer Risk
Liver and lung tumors
1.38E-06
High End
9.60E-05
3.84E-06
104
Central Tendency
4.29E-06
1.71E-07
1 Data from NTP (1986)
9
Exposures to ONUs were not able to be estimated separately from workers.
3 APF 25 and APF 50 are the two lowest APF allowable under OSHA standards for methylene chloride. EPA does
not assume routine use of PPE that would mitigate risk (respirator APF 25) with this condition of use in part because
only supplied air respirators can be used (see section 2.4.1.1). APF 50 not shown based on cancer risks at APF 25
are all less than the cancer risk benchmark of 10~4.
4.3.2.1.16 Spot Cleaning
Estimates of MOEs for acute and chronic exposures and cancer risks from inhalation for spot
cleaning are presented in Table 4-52, Table 4-53, and Table 4-54, respectively. For spot cleaning
exposure estimates for TWAs of 8 hrs are available based on personal monitoring data samples,
including 18 data points from 1 source (Finkel. 2017). EPA calculated 50th and 95th percentiles to
characterize the central tendency and high-end exposure estimates, respectively. EPA has not
identified data on potential ONU inhalation exposures from methylene chloride spot cleaning.
ONU inhalation exposures are expected to be lower than worker inhalation exposures however
the relative exposure of ONUs to workers cannot be quantified as described in more detail above
in Section 2.4.1.2.13. EPA calculated risk estimates assuming ONU exposures could be as high
as worker exposures as a high-end estimate and there is large uncertainty in this assumption.
Considering the overall strengths and limitations of the data, EPA's overall confidence in the
occupational inhalation estimates in this scenario is medium to low. Section 2.4.1.2.13 describes
the justification for this occupational scenario confidence rating. The studies that support the
health concerns of acute CNS effects, liver toxicity and cancer and the hazard value and
benchmark MOEs are described above in Section 4.3.1 Risk Estimation Approach and overall
EPA has medium confidence in the acute, chronic and cancer endpoints. Section 3.2.5.3
describes the justification for these confidence levels.
Table 4-52. Risk Estimation for Acute, Non-Cancer Inhalation Exposures for Spot
Cleaning				
MIX l ime Period
l.nripoinl = CNS IHTccls1
Acule
MIX
(111^/111')
l-lxposurc l.c\cl
MOI'.s lor Acnlt
Worker* ONI :
No rcspiralor
 Ixposii res
W orkcr
API- 25'
licnchmark MOI
(= Toial I I")
8-hr
290
High End
1.6
39
30
Central Tendency
436
10,896
1 Data from Putz et al. (1979
Page 395 of 753

-------
2	Exposures to ONUs were not able to be estimated separately from workers; also, this scenario covers a broad range
of industries and processes, which may result in significant differences between central and high-end exposures.
3	APF 25 and APF 50 are the two lowest APF allowable under OSHA standards for methylene chloride. EPA does
not assume routine use of PPE that would mitigate risk (respirator APF 25) with this condition of use in part because
only supplied air respirators can be used (see section 2.4.1.1). APF 50 not shown based onMOEs at APF 25 are all
greater than the benchmark MOE.
Table 4-53. Risk Estimation for Chronic, Non-Cancer Inhalation Exposures for Spot
Cleaning				
r.iiripoinl1
('limine
MIX
(iiiii/in1)
Exposure
1 .e\ el
MOI-'.s for Climi
Worker & OM :
No respirator
ie Exposures
Worker
API- 25'
lieiichmark
MOE
(= Tolal
I I)
Liver Effects
17.2
High End
0.41
10
10
Central
Tendency
113
2,830
1	Data from Nitschke et al. (1988a)
2	Exposures to ONUs were not able to be estimated separately from workers; also, this scenario covers a broad range
of industries and processes, which may result in significant differences between central and high-end exposures.
3	APF 25 and APF 50 are the two lowest APF allowable under OSHA standards for methylene chloride. EPA does
not assume routine use of PPE that would mitigate risk (respirator APF 25) with this condition of use in part because
only supplied air respirators can be used (see section 2.4.1.1). APF 50 not shown based on MOEs at APF 25 are all
greater than the benchmark MOE.
Table 4-54. Risk Estimation for Chronic. Cancer Inhalation Exposures for Spot Cleaning
I'lndpoini. Tumor
Tjpes"
11 K
(risk per ing/nr')
Exposure l.c\cl
Cancer Ris
Worker
OM : No
respiralor
; I'.sliinales
Worker
API- 25'
liciichmark
Cancer Risk
Liver and lung tumors
1.38E-06
High End
1.31E-04
5.25E-06
104
Central Tendency
3.66E-07
1.46E-08
1	Data from NTP (1986)
2	Exposures to ONUs were not able to be estimated separately from workers.
3	APF 25 and APF 50 are the two lowest APF allowable under OSHA standards for methylene chloride and are
considered plausible for respirator use. APF 50 not shown based on cancer risks at APF 25 are all less than the
cancer risk benchmark of 10~4.
4.3.2.1.17 Cellulose Triacetate Film Production
Estimates of MOEs for acute and chronic exposures and cancer risks from inhalation for CTA
film production are presented in Table 4-55, Table 4-56, and Table 4-57, respectively. For CTA
film production exposure estimates for TWAs of 8 hrs are available based on personal
monitoring data samples, including more than 100 data points from 6 studies compiled in 3
sources Dell eta I {I ^>9); JM > ,t_!\ ,'hs *)9); Ott et al I EPA calculated 50th and 95th
percentiles to characterize the central tendency and high-end exposure estimates, respectively.
EPA has not identified data on potential ONU inhalation exposures from methylene chloride
CTA film production. ONU inhalation exposures are expected to be lower than worker inhalation
exposures however the relative exposure of ONUs to workers cannot be quantified as described
Page 396 of 753

-------
in more detail above in Section 2.4.1.2.14. EPA calculated risk estimates assuming ONU
exposures could be as high as worker exposures as a high-end estimate and there is large
uncertainty in this assumption. Considering the overall strengths and limitations of the data,
EPA's overall confidence in the occupational inhalation estimates in this scenario is medium.
Section 2.4.1.2.14 describes the justification for this occupational scenario confidence rating.
The studies that support the health concerns of acute CNS effects, liver toxicity and cancer and
the hazard value and benchmark MOEs are described above in Section 4.3.1 Risk Estimation
Approach and overall EPA has medium confidence in the acute, chronic and cancer endpoints.
Section 3.2.5.3 describes the justification for these confidence levels.
Table 4-55. Risk Estimation for Acute, Non-Cancer Inhalation Exposures for Cellulose
Triacetate Film Production
MIX lime Period
r.iiripoini = CNS
i.nw-is1
Acule
MIX
(msi/mM
I'Aposlll'C
l.c\cl
MOI-'.s lor A
Worker & OM :
No respirator
ciilc llxposm
W orkcr
API- 25'
OS MOI.
W orkcr
API- 50'
licnchmark
MOI.
(= loliil
I 1)
8-hr
290
High End
0.21
5.2
10
30
Central
Tendency
0.28
7.0
14
1 Data from Putz et al. (1979)
2	Exposures to ONUs were not able to be estimated separately from workers.
3	APF 25 and APF 50 are the two lowest APF allowable under OSHA standards for methylene chloride and are
considered plausible for respirator use.
Table 4-56. Risk Estimation for Chronic, Non-Cancer Inhalation Exposures for Cellulose
Triacetate Film Production
Enripoinl1
Chronic
MIX
(ing/nr')
l-lxposurc
l.c\cl
MOI-'.s lor (
Worker & OM :
No rcspimlor
lironic l-'.\]
Worker
API- 25*
)osurcs
W orkcr
API- 50*
licnchmark
MOI.
(= To(;il
I 1)
Liver Effects
17.2
High End
0.05
1.3
2.7
10
Central
Tendency
0.07
1.8
3.6
1	Data from Nitschke et al. (.1.98831
2	Exposures to ONUs were not able to be estimated separately from workers.
3	APF 25 and APF 50 are the two lowest APF allowable under OSHA standards for methylene chloride and are
considered plausible for respirator use.
Table 4-57. Risk Estimation for Chronic, Cancer Inhalation Exposures for Cellulose
Triacetate Film Production
l-'.nripoinl. Tumor
T\pcs'
II K
(risk per
in *4/111
Exposure l.c\cl
Cancer Risk I-
Worker & ONI :
No respirator
slimalcs
Worker
API- 25*
licnchmark
Cancer Risk
Liver and lung tumors
1.38E-06
High End
7.67E-04
3.07E-05
104
Central Tendency
5.68E-04
2.27E-05
1 Data from NTP (1986)
Page 397 of 753

-------
9
Exposures to ONUs were not able to be estimated separately from workers.
3 APF 25 and APF 50 are the two lowest APF allowable under OSHA standards for methylene chloride and are
considered plausible for respirator use. APF 50 not shown based on cancer risks at APF 25 are all less than the
cancer risk benchmark of 10~4.
4.3.2.1.18 Plastic Product Manufacturing
Estimates of MOEs for acute and chronic exposures and cancer risks from inhalation for plastic
product manufacturing are presented in Table 4-58, Table 4-59, and Table 4-60, respectively. For
plastic product manufacturing exposure estimates for TWAs of 15 mins, and 8 hrs are available
based on personal monitoring data samples, including 62 data points from six sources OSHA.
(2019); Haloeemated Solvents Industry Alliance (2018); Fairfax and Porter (2006); WHO
U' >06b); General Electric C o v! i9): Finkel (2017). The 15 mins TWAs are useful for
characterizing exposures shorter than 8 hrs that could lead to adverse CNS effects. PODs specific
to 15 mins TWA exposures were used for characterization of the risk. EPA calculated 50th and
95th percentiles to characterize the central tendency and high-end exposure estimates,
respectively. Based on these strengths and limitations of the worker inhalation air concentration
data, the overall confidence for these 8-hr TWA data in this scenario is medium. EPA has
identified 1 data point on potential ONU inhalation exposures from methylene chloride plastic
product manufacturing as described in more detail above in Section 2.4.1.2.17. Considering the
overall strengths and limitations of the data, EPA's overall confidence in the occupational
inhalation estimate in this scenario is low for ONUs. Section 2.4.1.2.17 describes the justification
for this occupational scenario confidence rating. The studies that support the health concerns of
acute CNS effects, liver toxicity and cancer and the hazard value and benchmark MOEs are
described above in Section 4.3.1 Risk Estimation Approach and overall EPA has medium
confidence in the acute, chronic and cancer endpoints. Section 3.2.5.3 describes the justification
for these confidence levels.
Table 4-58. Risk Estimation for Acute, Non-Cancer Inhalation Exposures for Plastic
MIX Time
Period
l.nripoinl =
( NS IJIeels1
Aeule
MIC
(m^/iii
Kxposure
l.e\el
\1(
Workers
No respii'iilor
H-'.s for Aeule l.>
OM s
No respimlor
posures :
Workers
API 25'
lienehm;irk
moi:
(= loliil I I )
8-hr
290
High End
1.4
28
35
30
Central
Tendency
34
30
853
15-minute
1706
High End
13
--
328
30
Central
Tendency
21
517
1	Data from Putz et al. (1979)
2	This scenario covers a broad range of industries and processes, which may result in significant differences between
central and high-end exposures for workers. For ONU 15-minute TWA exposure data were not available to
characterize the central tendency and high end.
3	APF 25 and APF 50 are the two lowest APF allowable under OSHA standards for methylene chloride and are
considered plausible for respirator use.
Page 398 of 753

-------
Table 4-59. Risk Estimation for Chronic, Non-Cancer Inhalation Exposures for Plastic
r.mlpoinl1
Chronic
HEC
l'l\|)OMirc
l.c\cl
\\ orkcrs
No
rcspiralor
MOI-'.s 1
OM s
No
rcspiralor
or Chronic l-'.\posiirc
Workers
API- 25'
s 2
\\ orkcrs
API- 50'
benchmark
\ioi-:
(= loliil
I I)
Liver
Effects
17.2
High End
0.37
7.3
9.1
18
10
Central
Tendency
8.9
7.8
221
443
1	Data from Nitschke et al. (1988a)
2	This scenario covers a broad range of industries and processes, which may result in significant differences between
central and high-end exposures for workers.
3	APF 25 and APF 50 are the two lowest APF allowable under OSHA standards for methylene chloride and are
considered plausible for respirator use.
Table 4-60. Risk Estimation for Chronic, Cancer Inhalation Exposures for Plastic Product
Manufacturing				i	
Knripoinl. Tumor
Tj pes'
11 K
(risk pei'
mii/niM
l-lxposiirc l.c\cl
Ci
Worker
No
respirator
nccr Risk !"
ONIs No
rcspiralor
limalcs
Worker
API- 25:
licnchmark
Cancer Risk
Liver and lung tumors
1.38E-06
High End
1.46E-04
7.28E-06
5.83E-06
104
Central
Tendency
4.66E-06
5.31E-06
1.87E-07
1	Data from NTP (.1.986)
2	APF 25 and APF 50 are the two lowest APF allowable under OSHA standards for methylene chloride and are
considered plausible for respirator use. APF 50 not shown based on cancer risks at APF 25 are all less than the
cancer risk benchmark of 10~4.
4.3.2.1.19 Flexible Polyurethane Foam Manufacturing
Estimates of MOEs for acute and chronic exposures and cancer risks from inhalation for flexible
polyurethane foam manufacturing are presented in Table 4-61, Table 4-62, and Table 4-63,
respectively. For flexible polyurethane foam manufacturing exposure estimates for a TWA of 8
hrs are available based on personal monitoring data samples, including 84 data points from
multiple sources (i \Ul _ AM * , I ^ < \C 1 O) s f, Wlrk * lf 96b; Vulcan Chemicals. 1991; Rch
and Lushniak. 1990. H \ i 35; Cone Mills Corp. 198 l;t. h, Ulin Chemicals. 1977). EPA
calculated 50th and 95th percentiles to characterize the central tendency and high-end exposure
estimates, respectively. EPA has not identified data on potential ONU inhalation exposures from
methylene chloride flexible polyurethane foam manufacturing. ONU inhalation exposures are
expected to be lower than worker inhalation exposures however the relative exposure of ONUs
to workers cannot be quantified as described in more detail above in Section 2.4.1.2.11. EPA
calculated risk estimates assuming ONU exposures could be as high as worker exposures as a
high-end estimate and there is large uncertainty in this assumption. Considering the overall
strengths and limitations of the data, EPA's overall confidence in the occupational inhalation
estimates in this scenario is medium. Section 2.4.1.2.11 describes the justification for this
Page 399 of 753

-------
occupational scenario confidence rating. The studies that support the health concerns of acute
CNS effects, liver toxicity and cancer and the hazard value and benchmark MOEs are described
above in Section 4.3.1 Risk Estimation Approach and overall EPA has medium confidence in the
acute, chronic and cancer endpoints. Section 3.2.5.3 describes the justification for these
confidence levels.
Table 4-61. Risk Estimation for Acute, Non-Cancer Inhalation Exposures for Flexible
Polyurethane Foam Manufacturing		
lil t Time Period
l.mlpoim = ( NS
I'l'lecls1
Acule
MIX
(iiiii/m1)
l'l\|)OMIIV
1 .e\ el
MOI-'.s 1
Worker & <)M :
No respiralor
oi' Aeule l-'.\po
W orker
API- 25'
<11 res
W orker
API- 50'
lieiichmark
moi:
(= loliil I 1)
8-hr
290
High End
0.29
7.3
15
30
Central
Tendency
1.5
38
76
1 Data from Putz et al. (1979)
9
Exposures to ONUs were not able to be estimated separately from workers.
3 APF 25 and APF 50 are the two lowest APF allowable under OSHA standards for methylene chloride and are
considered plausible for respirator use. ONUs are not expected to wear respirators.
There are short term exposure data that allow estimation of 30-minute exposures (7 data points)
and 4-hr exposures (1 data point). Monitoring data to estimate a 15-min or 1-hr TWA exposure
were not available.
Table 4-62. Risk Estimation for Chronic, Non-Cancer Inhalation Exposures for Flexible
Polyurethane Foam Manufacturing		
I'lmlpoim1
( lironic
MIX
(11155/111')
l-'.\posure
1 .e\ el
MOI-'.s lor
Worker & OM :
No respiralor
('limine l'.\|
W orker
API- 25-'
losures
Worker
API- 50*
lieiichmark
MOI.
(= To(;il
I 1)
Liver Effects
17.2
High End
0.08
1.9
3.8
10
Central
Tendency
0.39
9.9
20
1	Data from Nitschke et al. (1988a)
2	Exposures to ONUs were not able to be estimated separately from workers.
3	APF 25 and APF 50 are the two lowest APF allowable under OSHA standards for methylene chloride and are
considered plausible for respirator use.
Table 4-63. Risk Estimation for Chronic, Cancer Inhalation Exposures for Flexible
Polyurethane Foam Manufacturing		
l-'.iidpoini. Tumor
Tjpes"
11 K
(risk per
111^/111 M
l-l\posiire
1 .e\ el
(a nee
Worker* ONI :
No respiralor
* Risk r.slimaU
Worker
API- 25*
:s
Worker
API- 50'
licnchmark
Cancer Risk
Liver and lung
tumors
1.38E-06
High End
7.06E-04
2.83E-05
1.41E-05
104
Central
Tendency
1.05E-04
4.19E-06
2.10E-06
1 Data from NTP (1986)
Page 400 of 753

-------
9
Exposures to ONUs were not able to be estimated separately from workers.
3 APF 25 and APF 50 are the two lowest APF allowable under OSHA standards for methylene chloride and are
considered plausible for respirator use.
4.3.2.1.20 Laboratory Use
Estimates of MOEs for acute and chronic exposures and cancer risks from inhalation for
laboratory use are presented in Table 4-64, Table 4-65, and Table 4-66, respectively. For
laboratory use exposure estimates for TWAs of 15 mins and 8 hrs are available based on
personal monitoring data samples, including 76 data points from multiple sources Defense
Occupational and Environmental Health Readiness System - Industrial Hvgie )EHRS~IH.)
(2018); Texaco Inc (1993); Mccamm.ti, r'X)); OSHA i-VI'l; f mket (2017). The 15 mins
TWAs are useful for characterizing exposures shorter than 8 hrs that could lead to adverse CNS
effects. PODs specific to 15 mins TWA exposures were used for characterization of the risk.
EPA calculated 50th and 95th percentiles to characterize the central tendency and high-end
exposure estimates, respectively. EPA has not identified data on potential ONU inhalation
exposures from methylene chloride laboratory use. ONU inhalation exposures are expected to be
lower than worker inhalation exposures however the relative exposure of ONUs to workers
cannot be quantified as described in more detail above in Section 2.4.1.2.16. EPA calculated risk
estimates assuming ONU exposures could be as high as worker exposures as a high-end estimate
and there is large uncertainty in this assumption. Considering the overall strengths and
limitations of the data, EPA's overall confidence in the occupational inhalation estimates in this
scenario is medium to low. Section 2.4.1.2.16 describes the justification for this occupational
scenario confidence rating. The studies that support the health concerns of acute CNS effects,
liver toxicity and cancer and the hazard value and benchmark MOEs are described above in
Section 4.3.1 Risk Estimation Approach and overall EPA has medium confidence in the acute,
chronic and cancer endpoints. Section 3.2.5.3 describes the justification for these confidence
levels.
Table 4-64. Risk Estimation for Acute, Non-Cancer Inhalation Exposures for Laboratory
Use
MIX l ime Period
l.nripoini = ( NS HITecls1
Acule lil t
(111^/111')
I'!\|)osiiiv l.e\el
MOI-'.s lor Acii
Worker & OM :
No ivspimlor
(e I'.\|)osiiivs
Worker
API- 25'
lienehniiii'k
MOI.
(= lohil
I I)
8-hr
290
High End
2.8
71
30
Central Tendency
48
1200
15-min
1706
High End
22
549
30
Central Tendency
256
6394
1	Data from Putz et al. (1979)
2	Exposures to ONUs were not able to be estimated separately from workers; also, this scenario covers a broad range
of industries and processes, which may result in significant differences between central and high-end exposures for
workers.
3	APF 25 and APF 50 are the two lowest APF allowable under OSHA standards for methylene chloride and are
considered plausible for respirator use. APF 50 not shown based on MOEs at APF 25 are all greater than the
benchmark MOE.
Page 401 of 753

-------
Table 4-65. Risk Estimation for Chronic, Non-Cancer Inhalation Exposures for
Laboratory Use				
l-'udpt tinl1
('limine
MIX
(iiiii/nr1)
l''.\poslll'C I.C\cl
MOI-'.s for ( limn
Worker & OM :
No respiralor
e l''.\|)osnres
Worker
API 25"'
licnchmark
MOI.
(= loliil
1 1 )
Liver Effects
17.2
High End
0.74
18
10
Central Tendency
12
312
1	Data from Nitschke et al. (1988a)
2	Exposures to ONUs were not able to be estimated separately from workers; also, this scenario covers a broad range
of industries and processes, which may result in significant differences between central and high-end exposures for
workers.
3	APF 25 and APF 50 are the two lowest APF allowable under OSHA standards for methylene chloride and are
considered plausible for respirator use. APF 50 not shown based on MOEs at APF 25 are all greater than the
benchmark MOE.
Table 4-66. Risk Estimation for Chronic, Cancer Inhalation Exposures for Laboratory Use
l-lnripoinl. Tumor
lApes1
11 K
(risk per
111^/111')
Exposure l.c\cl
Cancer Risk I-
Worker & OM :
No rcspiralor
slimalcs
Worker
API- 25'
benchmark
Cancer Risk
Liver and lung tumors
1.38E-06
High End
7.21E-05
2.89E-06
104
Central Tendency
3.31E-06
1.32E-07
1 Data from N IP (1986)
9
Exposures to ONUs were not able to be estimated separately from workers; also, this scenario covers a broad range
of industries and processes, which may result in significant differences between central and high-end exposures for
workers.
3	APF 25 and APF 50 are the two lowest APF allowable under OSHA standards for methylene chloride and are
considered plausible for respirator use. APF 50 not shown based on cancer risks at APF 25 are all less than the
cancer risk benchmark of 10~4.
4.3.2.1.21 Lithographic Printing Plate Cleaning
Estimates of MOEs for acute and chronic exposures and cancer risks from inhalation for
lithographic printing plate cleaning are presented in Table 4-67, Table 4-68, and Table 4-69,
respectively. For lithographic printing plate cleaning exposure estimates for TWAs of 8 hrs are
available based on personal monitoring data samples, including greater than 130 data points from
4	sources IJkai et al. (1998). s '85); Ahrenholz (1980); (Finkel. 2017). EPA calculated 50111
and 95th percentiles to characterize the central tendency and high-end exposure estimates,
respectively. EPA has not identified data on potential ONU inhalation exposures from methylene
chloride lithographic printing plate cleaning. ONU inhalation exposures are expected to be lower
than worker inhalation exposures however the relative exposure of ONUs to workers cannot be
quantified as described in more detail above in Section 2.4.1.2.18. EPA calculated risk estimates
assuming ONU exposures could be as high as worker exposures as a high-end estimate and there
is large uncertainty in this assumption. Considering the overall strengths and limitations of the
Page 402 of 753

-------
data, EPA's overall confidence in the occupational inhalation estimates in this scenario is
medium. Section 2.4.1.2.18 describes the justification for this occupational scenario confidence
rating. The studies that support the health concerns of acute CNS effects, liver toxicity and
cancer and the hazard value and benchmark MOEs are described above in Section 4.3.1 Risk
Estimation Approach and overall EPA has medium confidence in the acute, chronic and cancer
endpoints. Section 3.2.5.3 describes the justification for these confidence levels.
Table 4-67. Risk Estimation for Acute, Non-Cancer Inhalation Exposures for Lithographic
Printing Plate Cleaning			i	
MIX lime Period
l.nripoinl = CNS
l-flccls1
Acnlc
MIX
(in^/iiv1)
I'Aposlll'C
l.c\cl
MOI-slor A
Worker* OM :
No res|>ir;ilor
Mile Exposures MOT.
Worker
API- 25'
licnchmark
MOI.
(= lohil
1 1 )
8-hr
290
High End
1.8
45
30
Central
Tendency
33
832
1	Data from Putz et al. (1979)
2	Exposures to ONUs were not able to be estimated separately from workers; also, this scenario covers a broad range
of industries and processes, which may result in significant differences between central and high-end exposures.
3	APF 25 and APF 50 are the two lowest APF allowable under OSHA standards for methylene chloride. EPA does
not assume routine use of PPE that would mitigate risk (respirator APF 25 or 50) with this condition of use.
Table 4-68. Risk Estimation for Chronic, Non-Cancer Inhalation Exposures for
Lithographic Printing Plate Cleaning		
r.nripoini1
Chronic
MIX
(m *i/m
l-lxpoMirc
1 .c\ el
MOI-'.s for (
Worker* OM :
No rcspiralor
hi'onic Exposures
W orkcr
API- 25'
licnchmark
MOI.
(= lohil
1 1 )
Liver Effects
17.2
High End
0.47
12
10
Central
Tendency
8.7
216
1	Data from Nitschke et al. (1988a)
2	Exposures to ONUs were not able to be estimated separately from workers; also, this scenario covers a broad range
of industries and processes, which may result in significant differences between central and high-end exposures.
3	APF 25 and APF 50 are the two lowest APF allowable under OSHA standards for methylene chloride. EPA does
not assume routine use of PPE that would mitigate risk (respirator APF 25 or 50) with this condition of use.
Table 4-69. Risk Estimation for Chronic, Cancer Inhalation Exposures for Lithographic
Printing Plate Cleaning			
I'lndpoini. Tumor
Tjpes"
II K
(risk per
nig/in-')
Exposure l.e\el
Cancel' Risk I-
Worker* ONI :
No rcspiralor
slimalcs
Worker
API- 25'
licnchmark
Cancer Risk
Liver and lung tumors
1.38E-06
High End
1.13E-04
4.54E-06
104
Central Tendency
4.78E-06
1.91E-07
1 Data from NTP (.1.986)
9
Exposures to ONUs were not able to be estimated separately from workers; also, this scenario covers a broad range
of industries and processes, which may result in significant differences between central and high-end exposures.
Page 403 of 753

-------
3 APF 25 and APF 50 are the two lowest APF allowable under OSHA standards for methylene chloride. EPA does
not assume routine use of PPE that would mitigate risk (respirator APF 25) with this condition of use in part because
only supplied air respirators can be used (see section 2.4.1.1). APF 50 not shown based on cancer risks at APF 25
are all less than the cancer risk benchmark of 10~4.
4,3.2,2 Risk Estimation for Dermal Exposures to Workers
Estimates of MOEs for acute and chronic exposures and cancer risks from dermal exposures for
workers for all of the OESs are presented in Table 4-70, Table 4-71 and Table 4-72, respectively.
EPA calculated exposure estimates as described in more detail above in Section 2.4.1.1.
Considering these primary strengths and limitations, the overall confidence of the dermal dose
results is medium. The studies that support the health concerns of acute CNS effects, liver
toxicity and cancer and the hazard value and benchmark MOEs are described above in Section
4.3.1 Risk Estimation Approach. EPA conducted route-to-route extrapolation to derive the
dermal PODs and uncertainty factors. Overall EPA has medium confidence in the acute, chronic
and cancer endpoints. Section 3.2.5.3 describes the justification for these confidence levels.
Table 4-70. MOEs for Acute Dermal Exposures to Workers, by Occupational Exposure
()ccii|)iilion;il
Kxposurc Scenario
Sottin*
KxpOSIII'C
I.cm'I
Kxposurc
(mg/kg/ilsiv)
No
I'rolccliM'
(i lo\ OS
ll 1
No
I'rolccliM'
(iloM'S
I'l 1
MOI-sv
PI 5
illi (iIom
ll 10
ll s
ll 20
Manufacturing
industrial
Central
Tendency
0.75
21
107
NA
426
High-End
2.25
7.1
36
NA
142
Processing as a
Reactant
industrial
Central
Tendency
0.75
21
107
NA
426
High-End
2.25
7.1
36
NA
142
Processing -
Incorporation into
Formulation,
Mixture, or Reaction
Product
industrial
Central
Tendency
0.75
21
107
NA
426
High-End
2.25
7.1
36
NA
142
Repackaging
industrial
Central
Tendency
0.75
21
107
NA
426
High-End
2.25
7.1
36
NA
142
Waste Handling,
Disposal, Treatment,
and Recycling
industrial
Central
Tendency
0.75
21
107
NA
426
High-End
2.25
7.1
36
NA
142
Batch Open-Top
Vapor Degreasing
industrial
Central
Tendency
0.75
21
107
NA
426
High-End
2.25
7.1
36
NA
142
Conveyorized Vapor
Degreasing
industrial
Central
Tendency
0.75
21
107
NA
426
High-End
2.25
7.1
36
NA
142
Page 404 of 753

-------
()cciip;ilion;il
Kxposnre Scenario
Selling
Kxposnre
l.e\el
Kxposnre
(m/k/il:iy)
No
Protectee
(Jo\cs
PI 1
No
Prolecli\e
(Jo\cs
PI 1
MOKs v
PI 5
itll (ilOM
PI 10
PI s
PI 20
Cold Cleaning
industrial
Central
Tendency
0.75
21
1 ()7
NA
426
High-End
2 25
7.1

NA
142
Commercial Aerosol
Product Uses
commercial
Central
Tendency
1 :
14

136
NA
High-End
3 5
4.5
23
45
NA
Adhesives and
Sealants
industrial
Central
Tendency
0.75
21
1 ()7
NA
426
High-End
2 25
7.1

NA
142
Paints and Coatings
industrial/
commercial
Central
Tendency
0.75
21
107
NA
426
High-End
2 25
7.1

NA
142
Paint and Coating
Removers
industrial/
commercial
Central
Tendency
1 2
14

136
NA
High-End
3 5
4.5
23
45
NA
Adhesive and Caulk
Removers
commercial
Central
Tendency
1 1
15
75
151
NA
High-End
3 2
5.0
25
50
NA
Miscellaneous
Industrial Non-
Aerosol Use
industrial
Central
Tendency
0.75
21
107
NA
426
High-End
2 25
7.1

NA
142
Miscellaneous
Commercial Non-
Aerosol Use
commercial
Central
Tendency
1 2
14

136
NA
High-End
3 5
4.5
23
45
NA
Fabric Finishing
industrial/
commercial
Central
Tendency
1 1
14
71
143
NA
High-End
3 4
4.8
24
48
NA
Spot Cleaning
commercial
Central
Tendency
1 1
15
75
151
NA
High-End
3 2
5.0
25
50
NA
CTA Film
Manufacturing
industrial
Central
Tendency
0.75
21
107
NA
426
High-End
2 25
7.1

NA
142
Plastic Product
Manufacturing
industrial
Central
Tendency
0.75
21
107
NA
426
High-End
2 25
7.1

NA
142
Flexible
Polyurethane Foam
Manufacturing
industrial
Central
Tendency
0.75
21
107
NA
426
High-End
2 25
7.1

NA
142
Laboratory Use
industrial
Central
Tendency
1 IS
14

NA
271
High-End
3 5
4.5
23
NA
90

commercial
Central
Tendency
1 i)
15
77
153
NA
Page 405 of 753

-------
Occiip;ilion;il
Kxposnrc Sccnsirio
Lithographic
Printing Plate
Cleaner
Selling
Kxposnrc
I.CM'I
Kxposnrc
(m/k/il:iy)
No
I'rolccliM'
(iloM'S
PI 1
No
I'rolccliM'
(iloM'S
I'l 1
MOI-Isu
I'l 5
illi (iIom
I'l 10
I'l s
I'l 20
High-End
3 1
5.1
2(>
51
NA
NA not assessed because not all PFs are considered relevant to all conditions of use (COUs) and settings, see
Section 2.4.1.1
MOEs are less than benchmark MOEs when gloves are not worn for all OESs. When gloves are
used MOEs are greater than benchmark MOEs with PF 5 - 10 depending on the OES.
Table 4-71. MOEs for Chronic Dermal Exposures to Workers, by Occupational Exposure
Scenario for Liver Effects POD 2.15 mg/kg/day, Benchmark MOE = 10	
Occnpsilionsil
Kxposnrc
Sccnsirio
Sell in
Kxposnrc
I.CM'I
Kxposnrc
(in /k*/tl:i\)
No
I'rolccliM'
(ilOM'S
I'l 1
MO
No
I'rolccliM'
(iloM'S
I'l 1
!s lor l)if
I'l 5
fcrcnl I'l
I'l 10
I'l
20
Manufacturing
industrial
Central
Tendency
0.75
3.0
15
NA
60
High-End
2.25
1.0
5.0
NA
20
Processing as a
Reactant
industrial
Central
Tendency
0.75
3.0
15
NA
60
High-End
2.25
1.0
5.0
NA
20
Processing -
Incorporation into
Formulation,
Mixture, or
Reaction Product
industrial
Central
Tendency
0.75
3.0
15
NA
60
High-End
2.25
1.0
5.0
NA
20
Repackaging
industrial
Central
Tendency
0.75
3.0
15
NA
60
High-End
2.25
1.0
5.0
NA
20
Waste Handling,
Disposal,
Treatment, and
Recycling
industrial
Central
Tendency
0.75
3.0
15
NA
60
High-End
2.25
1.0
5.0
NA
20
Batch Open-Top
Vapor Degreasing
industrial
Central
Tendency
0.75
3.0
15
NA
60
High-End
2.25
1.0
5.0
NA
20
Conveyorized
Vapor Degreasing
industrial
Central
Tendency
0.75
3.0
15
NA
60
High-End
2.25
1.0
5.0
NA
20
Cold Cleaning
industrial
Central
Tendency
0.75
3.0
15
NA
60
Page 406 of 753

-------
()cciip;ilion;il
Kxposurc
Scenario
Sol liii
Kxposuiv
I.OM'I
Kxposurc
(in /k/cl)
No
IVollTtiM'
(iloM'S
ll 1
MO
No
IVoUTtiM'
(iloM'S
ll 1
!s lor l)if
ll 5
I'crcnl l>l
ll 10
PI
20
High-End
2.25
1.0
5.0
NA
20
Commercial
Aerosol Product
Uses
commercial
Central
Tendency
1.2
2.7
n
27
NA
High-End
3.5
0.90
4.4
9.0
NA
Adhesives and
Sealants
industrial
Central
Tendency
0.75
3.0
15
NA
60
High-End
2.25
1.0
5.0
NA
20
Paints and
Coatings
industrial/
commercial
Central
Tendency
0.75
3.0
15
NA
60
High-End
2.25
1.0
5.0
NA
20
Paint and Coating
Removers
industrial/
commercial
Central
Tendency
1.2
2.7
n
27
NA
High-End
3.5
0.90
4.4
9.0
NA
Adhesive and
Caulk Removers
commercial
Central
Tendency
1.1
3.0
15
3D
NA
High-End
3.2
0.98
4.8
9.7
NA
Miscellaneous
Industrial Non-
Aerosol Use
industrial
Central
Tendency
0.75
3.0
15
NA
60
High-End
2.25
1.0
5.0
NA
20
Miscellaneous
Commercial Non-
Aerosol Use
commercial
Central
Tendency
1.2
2.7
n
27
NA
High-End
3.5
0.90
4.4
9.0
NA
Fabric Finishing
industrial/
commercial
Central
Tendency
1.1
2.8
14
:s
NA
High-End
3.4
0.93
4.7
9.3
NA
Spot Cleaning
commercial
Central
Tendency
1.1
3.0
15
3D
NA
High-End
3.2
0.97
4.8
9.7
NA
CTA Film
Manufacturing
industrial
Central
Tendency
0.75
3.0
15
NA
60
High-End
2.25
1.0
5.0
NA
20
Plastic Product
Manufacturing
industrial
Central
Tendency
0.75
3.0
15
NA
60
High-End
2.25
1.0
5.0
NA
20
Flexible
Polyurethane
Foam
Manufacturing
industrial
Central
Tendency
0.75
3.0
15
NA
60
High-End
2.25
1.0
5.0
NA
20
Laboratory Use
industrial
Central
Tendency
1.2
2.7
n
27
NA
High-End
3.5
0.90
4.4
9.0
NA

commercial
Central
Tendency
1.0
3.0
15
3()
NA
Page 407 of 753

-------
Occiip;ilion;il
Kxposnrc
Scenario
Lithographic
Printing Plate
Cleaner
Selling
Kxposmv
I.OM'I
Kxposnrc
(in /k/cl)
No
I'roleclne
(iloM'S
ll 1
MO
No
I'rolccliM'
(iloM'S
ll 1
!s lor l)il'
ll 5
ci vil I l>l
ll 10
PI
20
High-End
3 1
1.0
5.0
10
NA
NA not assessed because not all PFs are considered relevant to all COUs and settings, see Section 2.4.1.1
MOEs are less than benchmark MOEs when gloves are not worn for all OESs. When gloves are
used MOEs are greater than benchmark MOEs for industrial uses with PF 20. MOEs are less
than benchmark MOEs for commercial uses with PF 10.
Table 4-72. Cancer Risk for Chronic Dermal Exposures to Workers, by Occupational
Exposure Scenario CSF 1.1 x 10 5 per mg/kg/day 	
()cciip:ilioiiiil
Kxposnrc
Scenario
Selling
Kxposmv
l.e\el
Kxposniv
(m/k/il:iy)
No
l'rolecli\e
(ilo\cs
ll 1
("sin
No
I'rolcclnc
(iloM'S
ll 1
cor Risk l o
ll 5
r DilTcivnl
ll 10
ll s
ll 20
Manufacturing
industrial
Central
Tendency
0.75
2.9E-06
5.8E-07
NA
1.45E-07
High-End
2.25
8.69E-06
1.74E-06
NA
4.35E-07
Processing as a
Reactant
industrial
Central
Tendency
0.75
2.9E-06
5.8E-07
NA
1.45E-07
High-End
2.25
8.69E-06
1.74E-06
NA
4.35E-07
Processing -
Incorporation
into
Formulation,
Mixture, or
Reaction
Product
industrial
Central
Tendency
0.75
2.9E-06
5.8E-07
NA
1.45E-07
High-End
2.25
8.69E-06
1.74E-06
NA
4.35E-07
Repackaging
industrial
Central
Tendency
0.75
2.9E-06
5.8E-07
NA
1.45E-07
High-End
2.25
8.69E-06
1.74E-06
NA
4.35E-07
Waste Handling,
Disposal,
Treatment, and
Recycling
industrial
Central
Tendency
0.75
2.9E-06
5.8E-07
NA
1.45E-07
High-End
2.25
8.69E-06
1.74E-06
NA
4.35E-07
Batch Open-Top
Vapor
Degreasing
industrial
Central
Tendency
0.75
2.9E-06
5.8E-07
NA
1.45E-07
High-End
2.25
8.69E-06
1.74E-06
NA
4.35E-07
Conveyorized
Vapor
Degreasing
industrial
Central
Tendency
0.75
2.9E-06
5.8E-07
NA
1.45E-07
High-End
2.25
8.69E-06
1.74E-06
NA
4.35E-07
Page 408 of 753

-------
()cciip;ilion;il
Kxposuiv
SiTiuirio
Solliii"
Kxposuiv
Lcm'I
Kxposuiv
(m/k/il:iy)
No
ProU'cli\e
(iloM'S
PI 1
Cnn
No
Prolecli\e
(i lo\ OS
PI 1
cor Risk l-'o
PI 5
r Different
PI 10
PI s
PI 20
Cold Cleaning
industrial
Central
Tendency
0.75
2.9E-06
5.8E-07
NA
1.45E-07
High-End
2.25
8.69E-06
1.74E-06
NA
4.35E-07
Commercial
Aerosol Product
Uses
commercial
Central
Tendency
1.2
4.5E-06
9.0E-07
4.5E-07
NA
High-End
3.5
1.35E-05
2.70E-06
1.35E-
06
NA
Adhesives and
Sealants
industrial
Central
Tendency
0.75
2.9E-06
5.8E-07
NA
1.45E-07
High-End
2.25
8.69E-06
1.74E-06
NA
4.35E-07
Paints and
Coatings
industrial/
commercial
Central
Tendency
0.75
2.9E-06
5.8E-07
NA
1.45E-07
High-End
2.25
8.69E-06
1.74E-06
NA
4.35E-07
Paint and
Coating
Removers
industrial/
commercial
Central
Tendency
1.2
4.5E-06
9.0E-07
4.5E-07
NA
High-End
3.5
1.35E-05
2.70E-06
1.35E-
06
NA
Adhesive and
Caulk Removers
commercial
Central
Tendency
1.1
4.3E-06
7.3E-07
4.3E-07
NA
High-End
3.2
1.26E-05
2.51E-06
1.26E-
06
NA
Miscellaneous
Industrial Non-
Aerosol Use
industrial
Central
Tendency
0.75
2.9E-06
5.8E-07
NA
1.45E-07
High-End
2.25
8.69E-06
1.74E-06
NA
4.35E-07
Miscellaneous
Commercial
Non-Aerosol
Use
commercial
Central
Tendency
1.2
4.5E-06
9.0E-07
4.5E-07
NA
High-End
3.5
1.35E-05
2.70E-06
1.35E-
06
NA
Fabric Finishing
industrial/
commercial
Central
Tendency
1.1
4.2E-06
8.4E-07
4.2E-07
NA
High-End
3.4
1.30E-05
2.61E-06
1.30E-
06
NA
Spot Cleaning
commercial
Central
Tendency
1.1
4.3E-06
7.3E-07
4.3E-07
NA
High-End
3.2
1.26E-05
2.51E-06
1.26E-
06
NA
CTA Film
Manufacturing
industrial
Central
Tendency
0.75
2.9E-06
5.8E-07
NA
1.45E-07
High-End
2.25
8.69E-06
1.74E-06
NA
4.35E-07
Plastic Product
Manufacturing
industrial
Central
Tendency
0.75
2.9E-06
5.8E-07
NA
1.45E-07
High-End
2.25
8.69E-06
1.74E-06
NA
4.35E-07

industrial
Central
Tendency
0.75
2.9E-06
5.8E-07
NA
1.45E-07
Page 409 of 753

-------
()cciip;ilion;il
Kxposnre
Scenario
Flexible
Polyurethane
Foam
Manufacturing
Selling
Kxposnre
Le\el
Kxposnre
(m/k/il:iy)
No
Prolecli\e
(iloM'S
PI 1
Cnn
No
Protect i\e
(i lo\ OS
PI 1
cor Risk l-'o
PI 5
r Different
PI 10
PI s
PI 20
High-End
2.25
8.69E-06
1.74E-06
NA
4.35E-07
Laboratory Use
industrial
Central
Tendency
1.2
4.5E-06
9.0E-07
4.5E-07
NA
High-End
3.5
1.35E-05
2.70E-06
1.35E-
06
NA
Lithographic
Printing Plate
Cleaner
commercial
Central
Tendency
1.0
3.9E-06
7.8E-07
3.9E-07
NA
High-End
3.1
1.21E-05
2.41E-06
1.21E-
06
NA
NA not assessed because not all PFs are considered relevant to all COUs and settings, see Section 2.4.1.1
Cancer risks are less than 10"4 when gloves are not worn for all OESs.
4.3.2.3 Risk Estimation for Inhalation and Dermal Exposures to Consumers
Estimates of MOEs for consumers were calculated for consumers for acute inhalation and dermal
exposures, because the exposure frequencies were not considered sufficient to cause the health
effects (i.e., liver effects and liver and lung tumors) that were observed in chronic animal studies
typically defined as at least 10% of the animal's lifetime.
4.3.2.3.1 Brake Cleaner
Estimates of MOEs for acute inhalation and dermal exposures for the brake cleaner consumer
use are presented in 4-72 and 4-73, respectively. Consumer inhalation and dermal exposures
were modeled across a range of low, moderate and high user intensities as described in detail in
Section 2.4.2. For inhalation, low, moderate and high intensity users are characterized by the
10th, 50th, and 95th percentile duration of use and mass of product used respectively and
minimum, midpoint, and maximum reported weight fractions where possible respectively.
Characterization of low intensity, moderate intensity and high intensity users for dermal
followed the same protocol as those described for the inhalation results, but only encompassing
the two varied duration of use and weight fraction parameters. Inhalation exposures are presented
for users and bystanders for TWAs of 1 hr and 8 hrs and dermal exposure results are presented
for users as acute ADRs in Section 2.4.2.4.5. Inhalation exposures were modeled for 27 different
scenarios, and dermal exposure was evaluated for nine scenarios (combinations of the duration of
use and weight fraction for receptors as adults and two youth age groups).
Considering the overall strengths and limitations of the data, EPA's overall confidence is high for
the consumer inhalation estimate and low to medium for the dermal estimate as discussed in
Section 2.4.2.6. The study that supports the CNS health concern is described above in Section
4.3.1. Overall, EPA has medium confidence in the acute endpoint, and Section 3.2.5.3 describes
the justification for this human health rating.
Page 410 of 753

-------
Table 4-73. Risk Estimation for Acute, Non-Cancer Inhalation Exposures for Brake
Cleaner Use
lll'X Time Period
llmlpoini = CNS HITecls1
Acule
MIX
(inii/in1)
l-lxposiirc Scenario
I scr
MOI.
li> slander
MOI.
licnchmark
moi:
(= Tolal
1 1 )


Low Intensity User
24
202

1-hr
840
Medium Intensity User
1.7
14
30


High Intensity User
0.43
2.3



Low Intensity User
50
218

8-hr
290
Medium Intensity User
3.6
15
30


High Intensity User
0.56
2.0

1 Data from Putz et al. (1979
The MOEs are < benchmark MOE for the 1 hr and 8 hr value high end and medium exposure
scenarios. Most MOEs are > benchmark MOE for the low exposures.
Table 4-74. Risk Estimation for Acute, Non-Cancer Dermal Exposures for Brake Cleaner
Use



Ariull I ser
licnchmark
MOI.
iiciiiih r.nvci
Acule II111)
(mii/kii/din)
l'l\|)OMire Scenario
Acule A 1)1)
(in ^/kii/(hi>)
MOI.
<= Tolal I I )
Impairment of
the CNS

Low Intensity User
0.068
234

16
Medium Intensity User
3.6
4.4
30

High Intensity User
49
0.32

For acute dermal exposures, MOEs are less than the benchmark MOE for consumer users for the
medium and high intensity user scenarios.
4.3.2.3.2 Carbon Remover
Estimates of MOEs for acute inhalation and dermal exposures for the carbon remover consumer
use are presented in Table 4-75 and Table 4-76, respectively. Consumer inhalation and dermal
exposures were modeled across a range of low, moderate, and high user intensities as described
in detail in Section 2.4.2. For inhalation, low, moderate and high intensity users are characterized
by the 10th, 50111, and 95th percentile duration of use and mass of product used respectively and
minimum, midpoint, and maximum reported weight fractions where possible respectively.
Characterization of low intensity, moderate intensity and high intensity users for dermal
followed the same protocol as those described for the inhalation results, but only encompassing
the two varied duration of use and weight fraction parameters. Inhalation exposures are
presented for users and bystanders for TWAs of 1 hr and 8 hrs and dermal exposure results are
presented for users as acute ADRs in Section 2.4.2.4.7. Inhalation exposures were modeled for
18 different scenarios and dermal exposure evaluated for six scenarios (combinations of the
duration of use and weight fraction for receptors as adults and two youth age groups)
Page 411 of 753

-------
Considering the overall strengths and limitations of the data, EPA's overall confidence is high for
the consumer inhalation estimate and low to medium for the dermal estimate, as discussed in
Section 2.4.2.6. The study that supports the CNS health concern is described above in Section
4.3.1. Overall, EPA has medium confidence in the acute endpoint, and Section 3.2.5.3 describes
the justification for this human health rating.
Table 4-75. Risk Estimation for Acute, Non-Cancer Inhalation Exposures for Carbon
Remover Use
lll'X Time Period
limlpoini = CNS HITeels1
Aeule
MIX
(inii/in1)
l-lxposure Seenario
I ser
MOI.
li> slander
MOI.
lienehmark
moi:
(= Tolal
1 1 )


Low Intensity User
9.5
103

1-hr
840
Medium Intensity User
0.94
9.7
30


High Intensity User
0.18
1.0



Low Intensity User
22
119

8-hr
290
Medium Intensity User
2.1
11
30


High Intensity User
0.23
0.93

1 Data from Putz et al. (1979)
The MOEs < benchmark MOE for both 1-hr and 8-hr exposures, except for the low exposure
bystanders.
The peak exposure value (4940 mg/m3) and the 1-hr maximum TWA (4750 mg/m3) for the high
intensity user identified in Section 2.4.2.4.7 do not exceed the NIOSH IDLH of 7981 mg/m3
(NIOSH. 1994) described in Section 3.2.3.1.1 but are greater than one half of the IDLH. The
NIOSH IDLH value was set to avoid situations that are immediately dangerous to life or health
and is a value above which individuals should not be exposed for any length of time.
Table 4-76. Risk Estimation for Acute, Non-Cancer Dermal Exposures for Carbon
Remover Use



Ariull I ser
lienehmark
MOI.
Health l l'lccl
Aeule III I)
l-lxpoMire Seeiiario
Aeule A 1)1)
(m )
moi:
(= Tolal I I")
Impairment of
the CNS

Low Intensity User
0.42
38

16
Medium Intensity User
5.5
2.9
30

High Intensity User
43.9
0.36

For acute dermal exposures, MOEs are less than the benchmark MOE for consumer users for the
medium and high intensity user scenarios.
Page 412 of 753

-------
4.3.2.3.3 Carburetor Cleaner
Estimates of MOEs for acute inhalation and dermal exposures for the carburetor cleaner
consumer use are presented in Table 4-77 and Table 4-78, respectively. Consumer inhalation and
dermal exposures were modeled across a range of low, moderate, and high user intensities as
described in detail in Section 2.4.2. For inhalation, low, moderate and high intensity users are
characterized by the 10th, 50th, and 95th percentile duration of use and mass of product used
respectively and minimum, midpoint, and maximum reported weight fractions where possible
respectively. Characterization of low intensity, moderate intensity and high intensity users for
dermal followed the same protocol as those described for the inhalation results, but only
encompassing the two varied duration of use and weight fraction parameters. Inhalation
exposures are presented for users and bystanders for TWAs of 1 hr and 8 hrs and dermal
exposure results are presented for users as acute ADRs in Section 2.4.2.4.8. Inhalation exposures
were modeled for 27 different scenarios and dermal exposure was evaluated for nine scenarios
(combinations of the duration of use and weight fraction for receptors as adults and two youth
age groups).
Considering the overall strengths and limitations of the data, EPA's overall confidence is high for
the consumer inhalation estimate and low to medium for the dermal estimate as discussed in
Section 2.4.2.6. The study that supports the CNS health concern is described above in Section
4.3.1. Overall, EPA has medium confidence in the acute endpoint, and Section 3.2.5.3 describes
the justification for this human health rating.
Table 4-77. Risk Estimation for Acute, Non-Cancer Inhalation Exposures for Carburetor
Cleaner Use
lll'X Time Period
r.mlpoiiii = ( NS I-'. Heels'
Aeule
MIX
(inii/in1)
I'lxposuiv Seen;irio
I ser
MOI.
IVtMiinriiT
MOI.
lienehniiirk
moi:
(= loliil
I I)


Low Intensity User
13
110

1-hr
840
Medium Intensity User
1.4
12
30


High Intensity User
0.28
2.0



Low Intensity User
27
118

8-hr
290
Medium Intensity User
3.0
13
30


High Intensity User
0.55
2.0

1 Data from Putz et al. (1979)
The MOEs < benchmark MOE for both 1-hr and 8-hr exposures, except for the low exposure
bystanders.
The peak exposure value (4420 mg/m3) for the high intensity user identified in Section 2.4.2.4.8
does not exceed the NIOSH IDLH of 7981 mg/m3 fNIOSH. 1994) described in Section 3.2.3.1.1
but is greater than one half of the IDLH. The NIOSH IDLH value was set to avoid situations that
are immediately dangerous to life or health and is a value above which individuals should not be
exposed for any length of time.
Page 413 of 753

-------
Table 4-78. Risk Estimation for Acute, Non-Cancer Dermal Exposures for Carburetor
Cleaner Use



Arinll I ser
licnchmark
MOI.
Health l l'lccl
Acule III I)
(inu/k^/da>)
I'A])omii'c Scenario
Acme A 1)1)
(m^/k^/da.t)
moi:
(= loial I I )
Impairment of
the CNS

Low Intensity User
0.10
158

16
Medium Intensity User
1.6
10
30

High Intensity User
16
1.0

For acute dermal exposures, MOEs are less than the benchmark MOE for consumer users for the
medium and high intensity user scenarios.
4.3.2.3.4 Coil Cleaner
Estimates of MOEs for acute inhalation and dermal exposures for the coil cleaner consumer use
are presented in 4-78 and 4-79, respectively. Consumer inhalation and dermal exposures were
modeled across a range of low, moderate, and high user intensities as described in detail in
Section 2.4.2. For inhalation, low, moderate and high intensity users are characterized by the
10th, 50th, and 95th percentile duration of use and mass of product used respectively and
minimum, midpoint, and maximum reported weight fractions where possible respectively.
Characterization of low intensity, moderate intensity and high intensity users for dermal
followed the same protocol as those described for the inhalation results, but only encompassing
the two varied duration of use and weight fraction parameters. Inhalation exposures are presented
for users and bystanders for TWAs of 1 hr and 8 hrs and dermal exposure results are presented
for users as acute ADRs in Section 2.4.2.4.9. Inhalation exposures were modeled for 18 different
scenarios and dermal exposure evaluated for six scenarios (combinations of the duration of use
and weight fraction for receptors as adults and two youth age groups).
Considering the overall strengths and limitations of the data, EPA's overall confidence is
medium to high for the consumer inhalation estimate and low to medium for the dermal estimate
as discussed in Section 2.4.2.6. The study that supports the CNS health concern is described
above in Section 4.3.1. Overall, EPA has medium confidence in the acute endpoint, and Section
3.2.5.3 describes the justification for this human health rating.
Table 4-79. Risk Estimation for Acute, Non-Cancer Inhalation Exposures for Coil Cleaner
Use
MIX l ime Period
llndpoinl = CNS r.lTecls1
Acnle
MIX
(in ii/iii")
l-lxpoMirc Scenario
I ser
MOI.
li\ slander
MOI.
licnchmark
moi:
(= Toial
1 1 )


Low Intensity User
5.5
60

1-hr
840
Medium Intensity User
0.57
5.9
30


High Intensity User
0.11
0.61

8-hr
290
Low Intensity User
13
69
30
Medium Intensity User
1.3
6.8
Page 414 of 753

-------


High Intensity User
0.14
0.57

1 Data from Putz et al. (1979)
The MOEs < benchmark MOE for both 1-hr and 8-hr exposures, except for the low exposure
bystanders at 8 hrs.
The peak exposure value (8080 mg/m3) and the 1-hr maximum TWA (7770 mg/m3) for the high
intensity user identified in Section 2.4.2.4.9 exceed the NIOSH IDLH of 7981 mg/m3 (KIOSK,
1994). The peak exposure value (4330 mg/m3) for the moderate intensity user (Section 2.4.2.4.9)
does not exceed the NIOSH IDLH but is greater than one half of the IDLH. The NIOSH IDLH
value was set to avoid situations that are immediately dangerous to life or health and is a value
above which individuals should not be exposed for any length of time.
Table 4-80. Risk Estimation for Acute, Non-Cancer Dermal Exposures for Coil Cleaner
Use



Ariull I NIT
licnchmark
MOI.
iiciiiih r.nvci
Acule II111)
l'l\|)OMire Scenario
Acule A 1)1)
(m;i/kii/(l;i\)
moi:
(= Tolal I I )
Impairment of
the CNS

Low Intensity User
0.72
22

16
Medium Intensity User
9.0
1.8
30

High Intensity User
72
0.22

For acute dermal exposures, MOEs are less than the benchmark MOE for consumer users for all
the exposure scenarios.
4.3.2.3.5 Electronics Cleaner
Estimates of MOEs for acute inhalation and dermal exposures for the electronics cleaner
consumer use are presented in Table 4-81 and Table 4-82, respectively. Consumer inhalation and
dermal exposures were modeled across a range of low, moderate, and high user intensities as
described in detail in Section 2.4.2. For inhalation, low, moderate and high intensity users are
characterized by the 10th, 50th, and 95111 percentile duration of use and mass of product used
respectively and minimum, midpoint, and maximum reported weight fractions where possible
respectively. Characterization of low intensity, moderate intensity and high intensity users for
dermal followed the same protocol as those described for the inhalation results, but only
encompassing the two varied duration of use and weight fraction parameters. Inhalation
exposures are presented for users and bystanders for TWAs of 1 hr and 8 hrs and dermal
exposure results are presented for users as acute ADRs in Section 2.4.2.4.11. Inhalation
exposures were modeled for nine different scenarios and dermal exposure evaluated for three
scenarios (combinations of the duration of use and a single identified weight fraction for
receptors as adults and two youth age groups).
Considering the overall strengths and limitations of the data, EPA's overall confidence is high for
the consumer inhalation estimate and low to medium for the dermal estimate as discussed in
Section 2.4.2.6. The study that supports the CNS health concern is described above in Section
Page 415 of 753

-------
4.3.1. Overall, EPA has medium confidence in the acute endpoint, and Section 3.2.5.3 describes
the justification for this human health rating.
Table 4-81. Risk Estimation for Acute, Non-Cancer Inhalation Exposures for Electronics
Cleaner Use
lll'X Time Period
llmlpoini = CNS HITecls1
Acule
MIX
(nig/nr,j
l-lxposiirc Scenario
I ser
MOI.
li> slander
MOI.
licnchmark
moi:
(= Tolal
1 1 )


Low Intensity User
1171
8027

1-hr
840
Medium Intensity User
91
633
30


High Intensity User
6.5
31



Low Intensity User
2492
10794

8-hr
290
Medium Intensity User
195
854
30


High Intensity User
13
46

1 Data from Putz et al. (1979)
The MOEs < benchmark MOE for both 1-hr and 8-hr exposures for high intensity users and high
intensity bystanders at 1 hr.
Table 4-82. Risk Estimation for Acute, Non-Cancer Dermal Exposures for Electronics
Cleaner Use



Ariull I ser
licnchmark
MOI.
iiciiiih r.nvci
Acule II111)
l'l\|)OMire Scenario
Acule A 1)1)
(in ^/kii/(hi>)
MOI.
<= Tolal I I )
Impairment of
the CNS

Low 1 Ilk'llsIlN L sor
U.U13
1208

16
Medium Intensity User
0.049
328
30

High Intensity User
0.25
64

For acute dermal exposures, MOEs are greater than the benchmark MOE for consumer users for
all the exposure scenarios.
4.3.2.3.6 Engine Cleaner
Estimates of MOEs for acute inhalation and dermal exposures for the engine cleaner consumer
use are presented in Table 4-83 and Table 4-84, respectively. Consumer inhalation and dermal
exposures were modeled across a range of low, moderate, and high user intensities as described
in detail in Section 2.4.2. For inhalation, low, moderate and high intensity users are
characterized by the 10th, 50th, and 95th percentile duration of use and mass of product used
respectively and minimum, midpoint, and maximum reported weight fractions where possible
respectively. Characterization of low intensity, moderate intensity and high intensity users for
dermal followed the same protocol as those described for the inhalation results, but only
encompassing the two varied duration of use and weight fraction parameters. Inhalation
exposures are presented for users and bystanders for TWAs of 1 hr and 8 hrs and dermal
exposure results are presented for users as acute ADRs in Section 2.4.2.4.12. Inhalation
Page 416 of 753

-------
exposures were modeled for 27 different scenarios and dermal exposure evaluated for nine
scenarios (combinations of the duration of use and weight fraction for receptors as adults and
two youth age groups).
Considering the overall strengths and limitations of the data, EPA's overall confidence is high for
the consumer inhalation estimate and low to medium for the dermal estimate as discussed in
Section 2.4.2.6. The study that supports the CNS health concern is described above in Section
4.3.1. Overall, EPA has medium confidence in the acute endpoint, and Section 3.2.5.3 describes
the justification for this human health rating.
Table 4-83. Risk Estimation for Acute, Non-Cancer Inhalation Exposures for Engine
Cleaner Use
lli:(' Time Period
l.nripoini = ( NS I-'.ITeels1
Aeule
MIX
(ing/nr*)
l'l\])OMire Seennrio
I ser
MOI.
IS> sliintler
MOI.
Benehniiirk
MOI.
(= Tolnl
I I)


Low Intensity User
5.4
47

1-hr
840
Medium Intensity User
0.62
5.1
30


High Intensity User
0.16
0.88



Low Intensity User
12
50

8-hr
290
Medium Intensity User
1.3
5.4
30


High Intensity User
0.22
0.77

1 Data from Putz et al. (1979)
The MOEs < benchmark MOE for both 1-hr and 8-hr exposures, except for the low exposure
bystanders.
Table 4-84. Risk Estimation for Acute, Non-Cancer Dermal Exposures for Engine Cleaner
Use



Ariull I ser
lienehniiirk
MOI.
lleiillh F.ITeel
Aeule lll'.l)
(mii/kii/din)
l'l\|)OMire Seeiiiii'io
Aeule A 1)1)
(in ^/kii/(hi>)
MOI.
(= lolal I I )
Impairment of
the CNS

Low Intensity User
0.51
32

16
Medium Intensity User
3.4
4.7
30

High Intensity User
42
0.38

For acute dermal exposures, MOEs are less than the benchmark MOE for consumer users for the
medium and high intensity user scenarios.
The peak exposure value (5480 mg/m3) and the 1-hr maximum TWA (5100 mg/m3) for the high
intensity user identified in Section 2.4.2.4.12 do not exceed the NIOSH IDLH of 7981 mg/m3
("NIOSH. 1994) described in Section 3.2.3.1.1 but are greater than one half of the IDLH. The
NIOSH IDLH value was set to avoid situations that are immediately dangerous to life or health
and is a value above which individuals should not be exposed for any length of time.
Page 417 of 753

-------
4.3.2.3.7 Gasket Remover
Estimates of MOEs for acute inhalation and dermal exposures for the gasket remover consumer
use are presented in Table 4-85 and Table 4-86, respectively. Consumer inhalation and dermal
exposures were modeled across a range of low, moderate, and high user intensities as described
in detail in Section 2.4.2. For inhalation, low, moderate and high intensity users are characterized
by the 10th, 50th, and 95th percentile duration of use and mass of product used respectively and
minimum, midpoint, and maximum reported weight fractions where possible respectively.
Characterization of low intensity, moderate intensity and high intensity users for dermal
followed the same protocol as those described for the inhalation results, but only encompassing
the two varied duration of use and weight fraction parameters. Inhalation exposures are presented
for users and bystanders for TWAs of 1 hr and 8 hrs and dermal exposure results are presented
for users as acute ADRs in Section 2.4.2.4.13. Inhalation exposures were modeled for 18
different scenarios and dermal exposure was evaluated for six scenarios (combinations of the
duration of use and weight fraction for receptors as adults and two youth age groups).
Considering the overall strengths and limitations of the data, EPA's overall confidence is high for
the consumer inhalation estimate and low to medium for the dermal estimate, as discussed in
Section 2.4.2.6. The study that supports the CNS health concern is described above in Section
4.3.1. Overall, EPA has medium confidence in the acute endpoint, and Section 3.2.5.3 describes
the justification for this human health rating.
Table 4-85. Risk Estimation for Acute, Non-Cancer Inhalation Exposures for Gasket
Remover Use
lll'X Time Period
l.mlpoinl = ( NS HITeels1
Acule
MIX
(inii/in1)
l-lxposiirc Scenario
I ser
MOI.
li> slander
MOI.
licnchmark
moi:
(= Tolal
I I)


Low Intensity User
5.9
51

1-hr
840
Medium Intensity User
1.1
9.1
30


High Intensity User
0.22
1.4



Low Intensity User
13
55

8-hr
290
Medium Intensity User
2.3
9.7
30


High Intensity User
0.42
1.4

1 Data from Putz et al. (1979)
The MOEs < benchmark MOE for both 1-hr and 8-hr exposures, except for the low intensity
bystanders.
Table 4-86. Risk Estimation for Acute, Non-Cancer Dermal Exposures for Gasket Remover
Use
iiciiiih r.nvci
Acule II111)
(mii/kii/din)
l'l\|)OMire Scenario
Ariull
Acule A 1)1)
(in )
I ser
MOI.
licnchmark
MOI.
(= Tolal I I )
Impairment of
the CNS
16
Low Intensity User
0.56
29
30
Medium Intensity User
5.6
2.9
Page 418 of 753

-------


High Intensity User
22
0.72

For acute dermal exposures, MOEs are less than the benchmark MOE for consumer users for the
medium and high intensity user scenarios.
The peak exposure value (5120 mg/m3) for the high intensity user identified in Section 2.4.2.4.13
does not exceed the NIOSH IDLH of 7981 mg/m3 ("NIOSH, 1994) described in Section 3.2.3.1.1
but is greater than one half of the IDLH. The NIOSH IDLH value was set to avoid situations that
are immediately dangerous to life or health and is a value above which individuals should not be
exposed for any length of time.
4.3.2.3.8 Adhesives
Estimates of MOEs for acute inhalation and dermal exposures for the adhesive consumer use are
presented in Table 4-87 and Table 4-88, respectively. Consumer inhalation and dermal exposures
were modeled across a range of low, moderate, and high user intensities as described in detail in
Section 2.4.2. For inhalation, low, moderate and high intensity users are characterized by the
10th, 50th, and 95th percentile duration of use and mass of product used respectively and
minimum, midpoint, and maximum reported weight fractions where possible respectively.
Characterization of low intensity, moderate intensity and high intensity users for dermal
followed the same protocol as those described for the inhalation results, but only encompassing
the two varied duration of use and weight fraction parameters. Inhalation exposures are presented
for users and bystanders for TWAs of 1 hr and 8 hrs and dermal exposure results are presented
for users as acute ADRs in Section 2.4.2.4.1. Inhalation exposures were modeled for 27 different
scenarios and dermal exposure was evaluated for nine scenarios (combinations of the duration of
use and weight fraction for receptors as adults and two youth age groups).
Considering the overall strengths and limitations of the data, EPA's overall confidence is high for
the consumer inhalation estimate and low to medium for the dermal estimate as discussed in
Section 2.4.2.6. The study that supports the CNS health concern is described above in Section
4.3.1. Overall, EPA has medium confidence in the acute endpoint, and Section 3.2.5.3 describes
the justification for this human health rating.
Table 4-87. Risk Estimation for Acute, Non-Cancer Inhalation Exposures for Adhesives
Use
lli:(' Time Period
l.mlpninl = ( NS I-'.ITeels1
Aeule
MIX
(in <4/111')
l'l\|)osiire Seeiiiii'io
I ser
MOI.
IS> sliintler
MOI.
lieiiehniiirk
MOI.
(= lohil
I I)


Low Intensity User
199
2188

1-hr
840
Medium Intensity User
12
130
30


High Intensity User
0.53
4.2



Low Intensity User
452
2535

8-hr
290
Medium Intensity User
27
150
30


High Intensity User
1.1
4.7

1 Data from Putz et al. (1979)
Page 419 of 753

-------
The MOEs are < benchmark MOE for the 1 hr and 8 hr values high end exposure scenarios.
The MOEs are > benchmark MOE for most medium and low exposure scenarios.
Table 4-88. Risk Estimation for Acute, Non-Cancer Dermal Exposures for Adhesives Use



Arinll I ser
licnchmark
moi:
lk-;il111 1". ITcci
Acule II111)
(m^/k^/da>)
l'l\|)(Mire Scenario
Acme A 1)1)
(m^/k^/(la>)
moi:
(= Total I I )
Impairment of
the CNS

Low Intensity User
0.04
372

16
Medium Intensity User
0.60
27
30

High Intensity User
2.55
6.3

For acute dermal exposures, MOEs are less than the benchmark MOE for consumer users for the
medium and high intensity user scenarios.
4.3.2.3.9 Auto Leak Sealer
Estimates of MOEs for acute inhalation and dermal exposures for auto leak sealing consumer
uses are presented in Table 4-89 and Table 4-90, respectively. Consumer inhalation and dermal
exposures were modeled across a range of low, moderate, and high user intensities as described
in detail in Section 2.4.2. For inhalation, low, moderate and high intensity users are characterized
by the 10th, 50th, and 95th percentile duration of use and mass of product used respectively and
minimum, midpoint, and maximum reported weight fractions where possible respectively.
Characterization of low intensity, moderate intensity and high intensity users for dermal
followed the same protocol as those described for the inhalation results, but only encompassing
the two varied duration of use and weight fraction parameters. Inhalation exposure for users and
bystanders for TWAs of 1 hr and 8 hrs and dermal exposure results for users as acute ADRs are
described in Section 2.4.2.4.1. Inhalation and dermal exposures were modeled for three different
scenarios respectively (combinations of the duration of use and a single value for weight fraction
for receptors as adults and two youth age groups)
Considering the overall strengths and limitations of the data, EPA's overall confidence is
medium to high for the consumer inhalation estimate and low to medium for the dermal estimate
as discussed in Section 2.4.2.6. The study that supports the CNS health concern is described
above in Section 4.3.1. Overall, EPA has medium confidence in the acute endpoint described in
Section 3.2.5.3.
Table 4-89. Risk Estimation for Acute, Non-Cancer Inhalation Exposures for Auto Leak
Sealer Use
MIX l ime Period
l.ndpoint = CNS F.ITecis"
Acnle
MIX
(inii/in1)
l'l\poMirc Scenario
I ser
MOI.
lij slander
MOI.
licnchmark
moi:
(= Total
I I)
1-hr
840
Low Intensity User
120
1031
30
Medium Intensity User
123
1015
Page 420 of 753

-------


High Intensity User
210
1117

8-hr
290
Low Intensity User
255
1107
30
Medium Intensity User
259
1077
High Intensity User
274
980
1 Data from Putz et al. (1979)
For acute inhalation exposures, MOEs are less than the benchmark MOE for consumer users and
bystanders at 1-hr and 8-hr exposures for all the exposure scenarios.
Table 4-90. Risk Estimation for Acute, Non-Cancer Dermal Exposures for Auto Leak
Sealer Use



Arinll I ser
licnchmark
MOF.
lleallh l.llecl
Acule III I)
(m^/k^/(la>)
Fxposiirc Scenario
Acme \l)l)
(m^/k^/(la>)
MOF.
(= loial I I )
Impairment of
the CNS

Low Intensity User
1.65
10

16
Medium Intensity User
3.23
5.0
30

High Intensity User
4.1
3.9

For acute dermal exposures, MOEs are less than the benchmark MOE for consumer users for all
the exposure scenarios.
4.3.2.3.10 Brush Cleaner
Estimates of MOEs for acute inhalation and dermal exposures for the brush cleaner consumer
use are presented in Table 4-91 and Table 4-92, respectively. Consumer inhalation and dermal
exposures were modeled across a range of low, moderate, and high user intensities as described
in detail in Section 2.4.2. For inhalation, low, moderate and high intensity users are characterized
by the 10th, 50th, and 95th percentile duration of use and mass of product used respectively and
minimum, midpoint, and maximum reported weight fractions where possible respectively.
Characterization of low intensity, moderate intensity and high intensity users for dermal
followed the same protocol as those described for the inhalation results, but only encompassing
the two varied duration of use and weight fraction parameters. Inhalation exposures are presented
for users and bystanders for TWAs of 1 hr and 8 hrs and dermal exposure results are presented
for users as acute ADRs in Section 2.4.2.4.6. Inhalation exposures were modeled for nine
different scenarios and dermal exposure was evaluated for three scenarios (combinations of the
duration of use and a weight fraction for receptors as adults and two youth age groups).
Considering the overall strengths and limitations of the data, EPA's overall confidence is
medium to high for the consumer inhalation estimate and low to medium for the dermal estimate
as discussed in Section 2.4.2.6. The study that supports the CNS health concern is described
above in Section 4.3.1. Overall, EPA has medium confidence in the acute endpoint, and Section
3.2.5.3 describes the justification for this human health rating.
Page 421 of 753

-------
Table 4-91. Risk Estimation for Acute, Non-Cancer Inhalation Exposures for Brush
Cleaner Use
lli:(' Time Period
l.mlpoim = ( NS I-'.ITeels1
Aeule
MIX
(in ii/iii")
l-lxposure Seenario
I ser
MOI.
IS> sliintler
MOI.
lienehmark
MOI.
(= Tolal
I I)


Low Intensity User
3956
44077

1-hr
840
Medium Intensity Us